Im working on a 3D platformer where theres a large platform and a character made up of multiple cubes.
However when I try rotating the Y axis of the characters cubes it doesn't rotate them at their centerpoint. They just orbit as a whole around the platform in a huge circle. I'm guessing my glRotatef's are in the wrong order but I cant seem to figure out what order they should be to make the group of cubes rotate only around their center point.
My code for drawing them is:
for (int i = 0; i < Models.size(); i++){ // theres only one model this has to go through that stores the group of cubes for the character
glPushMatrix(); // set rotation for the whole group (I would expect...)
glRotatef(Models.at(i)->ModelRotation.X,1,0,0);
glRotatef(Models.at(i)->ModelRotation.Y,0,1,0);
glRotatef(Models.at(i)->ModelRotation.Z,0,0,1);
for (int j = 0; j < Models.at(i)->Parts.size(); j++) // For each cube in the character,
Models.at(i)->Parts.at(j)->Render(); // draw the cube
glPopMatrix();
}
Model is a struct that just has a vector3 called "ModelRotation" and a normal vector called "Parts" which stores all the cubes for the character.
My function for rendering the cube in the cube class is:
void Render(){
glPushMatrix();
glTranslatef( Position.X,
Position.Y,
Position.Z
);
glColor3f( Color.R,
Color.G,
Color.B
);
glScalef( Size.X,
Size.Y,
Size.Z
);
// Render the front quad
//glBindTexture(GL_TEXTURE_2D, Faces[0]);
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( 1.0f, -1.0f, -1.0f );
glTexCoord2f(1, 0); glVertex3f( -1.0f, -1.0f, -1.0f );
glTexCoord2f(1, 1); glVertex3f( -1.0f, 1.0f, -1.0f );
glTexCoord2f(0, 1); glVertex3f( 1.0f, 1.0f, -1.0f );
glEnd();
// Render the left quad
//glBindTexture(GL_TEXTURE_2D, Faces[1]);
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( 1.0f, -1.0f, 1.0f );
glTexCoord2f(1, 0); glVertex3f( 1.0f, -1.0f, -1.0f );
glTexCoord2f(1, 1); glVertex3f( 1.0f, 1.0f, -1.0f );
glTexCoord2f(0, 1); glVertex3f( 1.0f, 1.0f, 1.0f );
glEnd();
// Render the back quad
//glBindTexture(GL_TEXTURE_2D, Faces[2]);
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( -1.0f, -1.0f, 1.0f );
glTexCoord2f(1, 0); glVertex3f( 1.0f, -1.0f, 1.0f );
glTexCoord2f(1, 1); glVertex3f( 1.0f, 1.0f, 1.0f );
glTexCoord2f(0, 1); glVertex3f( -1.0f, 1.0f, 1.0f );
glEnd();
// Render the right quad
//glBindTexture(GL_TEXTURE_2D, Faces[3]);
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( -1.0f, -1.0f, -1.0f );
glTexCoord2f(1, 0); glVertex3f( -1.0f, -1.0f, 1.0f );
glTexCoord2f(1, 1); glVertex3f( -1.0f, 1.0f, 1.0f );
glTexCoord2f(0, 1); glVertex3f( -1.0f, 1.0f, -1.0f );
glEnd();
// Render the top quad
//glBindTexture(GL_TEXTURE_2D, Faces[4]);
glBegin(GL_QUADS);
glTexCoord2f(0, 1); glVertex3f( -1.0f, 1.0f, -1.0f );
glTexCoord2f(0, 0); glVertex3f( -1.0f, 1.0f, 1.0f );
glTexCoord2f(1, 0); glVertex3f( 1.0f, 1.0f, 1.0f );
glTexCoord2f(1, 1); glVertex3f( 1.0f, 1.0f, -1.0f );
glEnd();
// Render the bottom quad
//glBindTexture(GL_TEXTURE_2D, Faces[5]);
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( -1.0f, -1.0f, -1.0f );
glTexCoord2f(0, 1); glVertex3f( -1.0f, -1.0f, 1.0f );
glTexCoord2f(1, 1); glVertex3f( 1.0f, -1.0f, 1.0f );
glTexCoord2f(1, 0); glVertex3f( 1.0f, -1.0f, -1.0f );
glEnd();
glPopMatrix();
};
Any help would be very much appreciated.
I'm guessing it's just a simple mistake I can't put together.
I'll show more code if it's needed.
The way OpenGL applies the transformations is from bottom to top between PopMatrix() and PushMatrix(), that is the inverse from the way you are actually coding them.
In your code, the order in which you are calling is flipped like this:
Rotatef();
Translatef();
Scalef();
It should be:
Translatef();
Rotatef();
Scalef();
In other words, you want to translate always as last (meaning putting it into your code as the very first line after the PopMatrix()) unless you have a good reason (a particular graphic effect or scene rendering), so that you first apply scaling and rotation transformations and then you translate the object in world coordinates.
For rotating multipart objects (as your case) you should probably translate twice, as explained here: Rotating a multipart object
So your code outside the cube class could be something like:
for (int i = 0; i < Models.size(); i++){
glPushMatrix();
glTranslatef(
Models.at(i)->WorldPosition.X,
Models.at(i)->WorldPosition.Y,
Models.at(i)->WorldPosition.Z,
);
glRotatef(Models.at(i)->ModelRotation.X,1,0,0);
glRotatef(Models.at(i)->ModelRotation.Y,0,1,0);
glRotatef(Models.at(i)->ModelRotation.Z,0,0,1);
for (int j = 0; j < Models.at(i)->Parts.size(); j++)
Models.at(i)->Parts.at(j)->Render(); // draw the cube
glPopMatrix();
}
Related
I am currently rendering a solar system of planets in my 3d space but every single planet is black even when light hits the sphere. The spheres are rendered last in my render function. Had the colors working when the spheres were being rendered on their own but now i've added my sky box and other quads all the spheres refuse to be colored.
#include "Scene.h"
float rotation;
float rotation2;
int direction;
int speed;
Scene::Scene(Input *in)
{
// Initialise variables
rotation = 20;
rotation2 = 0;
direction = 1;
speed = 5;
myTexture = 0;
skyBox = 0;
// Store pointer for input class
input = in;
// OpenGL settings
glShadeModel(GL_SMOOTH); // Enable Smooth Shading
glClearColor(0.39f, 0.58f, 93.0f, 1.0f); // Cornflour Blue Background
glClearDepth(1.0f); // Depth Buffer Setup
glClearStencil(0); // Clear stencil buffer
glEnable(GL_DEPTH_TEST); // Enables Depth Testing
glEnable(GL_LIGHTING); // Enables Lighting
glDepthFunc(GL_LEQUAL); // The Type Of Depth Testing To Do
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really Nice Perspective Calculations
// Other OpenGL / render setting should be applied here.
myTexture = SOIL_load_OGL_texture
(
"gfx/neongrid.png",
SOIL_LOAD_AUTO,
SOIL_CREATE_NEW_ID,
SOIL_FLAG_MIPMAPS | SOIL_FLAG_NTSC_SAFE_RGB | SOIL_FLAG_COMPRESS_TO_DXT
);
skyBox = SOIL_load_OGL_texture
(
"gfx/starField.png",
SOIL_LOAD_AUTO,
SOIL_CREATE_NEW_ID,
SOIL_FLAG_MIPMAPS | SOIL_FLAG_NTSC_SAFE_RGB | SOIL_FLAG_COMPRESS_TO_DXT
);
glEnable(GL_TEXTURE_2D);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_NEAREST);
camera = new Camera();
}
void Scene::update(float dt)
{
// Update camera position
camera->update(input, dt);
// Handle user input
if (input->isKeyDown(43))
{
direction = 1;
input->SetKeyUp(43);
}
else if (input->isKeyDown(45))
{
direction = -1;
input->SetKeyUp(45);
}
// Update scene related variables
rotation += speed * dt;
rotation2 += (speed *2) * dt;
if (input->isKeyDown('p') && WF == false)
{
WF = true;
input->SetKeyUp('p');
glPolygonMode(GL_FRONT, GL_LINE);
}
if (input->isKeyDown('p') && WF == true)
{
WF = false;
input->SetKeyUp('p');
glPolygonMode(GL_FRONT, GL_FILL);
}
// Calculate FPS for output
calculateFPS();
}
void Scene::render() {
// Clear Color and Depth Buffers
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Reset transformations
glLoadIdentity();
// Set the camera
gluLookAt(camera->getPosition().x, camera->getPosition().y, camera->getPosition().z,
camera->getLookAt().x, camera->getLookAt().y, camera->getLookAt().z,
camera->getUp().x, camera->getUp().y, camera->getUp().z);
glutWarpPointer(400, 300);
glutSetCursor(GLUT_CURSOR_FULL_CROSSHAIR);
// Lighting
GLfloat Light_Ambient[] = { 0.2f, 0.2f, 0.2f, 1.0f };
GLfloat Light_Diffuse[] = { 9.0f, 9.0f, 9.0f, 1.0f };
GLfloat Light_Position[] = { 2.0f, 2.0f, 2.0f, 1.0f };
glLightfv(GL_LIGHT0, GL_AMBIENT, Light_Ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, Light_Diffuse);
glLightfv(GL_LIGHT0, GL_POSITION, Light_Position);
glEnable(GL_LIGHT0);
glDisable(GL_DEPTH_TEST);
#pragma region skybox
glPushMatrix();
glTranslatef(camera->getPosition().x, camera->getPosition().y, camera->getPosition().z);
glBindTexture(GL_TEXTURE_2D, skyBox);
glBegin(GL_QUADS);
//Back
glNormal3f(0.0f, 0.0f, 1.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
glNormal3f(0.0f, 0.0f, 1.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
glNormal3f(0.0f, 0.0f, 1.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glNormal3f(0.0f, 0.0f, 1.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
//Right
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(1.0f, -1.0f, -1.0f);
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
//front
glNormal3f(0.0f, 0.0f, -1.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, -1.0f);
glNormal3f(0.0f, 0.0f, -1.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glNormal3f(0.0f, 0.0f, -1.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
glNormal3f(0.0f, 0.0f, -1.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
//left
glNormal3f(-1.0f, 0.0f, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glNormal3f(-1.0f, 0.0f, 0.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
glNormal3f(-1.0f, 0.0f, 0.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glNormal3f(-1.0f, 0.0f, 0.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
//top
glNormal3f(0.0f, 1.0f, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glNormal3f(0.0f, 1.0f, 0.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glNormal3f(0.0f, 1.0f, 0.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
glNormal3f(0.0f, 1.0f, 0.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
//bottom
glNormal3f(0.0f, -1.0f, 0.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glNormal3f(0.0f, -1.0f, 0.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(1.0f, -1.0f, -1.0f);
glNormal3f(0.0f, -1.0f, 0.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
glNormal3f(0.0f, -1.0f, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
glEnd();
#pragma endregion
glEnable(GL_DEPTH_TEST);
glPopMatrix();
glPushMatrix();
#pragma region wall
glBindTexture(GL_TEXTURE_2D, myTexture);
glTranslatef(0.0, 0.0, 0.0);
glScalef(5.0f, 5.0f, 5.0f);
glBegin(GL_QUADS);
// first face
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(0.0f, 1.0f, 0.0f);
// second face
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(1.0f, 1.0f, 0.0f);
// third face
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(1.0f, 0.0f, 0.0f);
// fourth face
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(0.0f, 0.0f, 0.0f);
glEnd();
glPopMatrix();
glPushMatrix();
glBindTexture(GL_TEXTURE_2D, myTexture);
glScalef(5.0f, 5.0f, 5.0f);
glBegin(GL_QUADS);
// first face
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(0.0f, 0.0f, 0.0f);
// second face
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(1.0f, 0.0f, 0.0f);
// third face
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(1.0f, 0.0f, -1.0f);
// fourth face
glNormal3f(1.0f, 0.0f, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(0.0f, 0.0f, -1.0f);
glEnd();
#pragma endregion
glPopMatrix();
glPushMatrix();
// Render sun
glEnable(GL_TEXTURE_2D);
glColor3f(1.0f, 1.0f, 1.0f);
glBindTexture(GL_TEXTURE_2D, NULL);
glTranslatef(0.5, 0.5, -0.5);
glColor3f(1.0f, 0.0f, 0.0f);
gluSphere(gluNewQuadric(), 0.20, 20, 20);
glPushMatrix(); // Push for default matrix
// Render Planet 1
glRotatef(rotation, 0.5, 0.5, 0);
glTranslatef(0, 0, 1);
glScalef(1, 1, 1);
glColor3f(0.0f, 2.0f, 0.0f);
gluSphere(gluNewQuadric(), 0.20, 10, 10);
glPopMatrix(); // Pop off stack back to sun matrix
glPushMatrix(); // Push for default matrix
// Render Planet 2
glRotatef(rotation2, 0, 1, 0);
glTranslatef(2, 0, 0);
glScalef(0.5, 0.5, 0.5);
glColor3f(0.0f, 0.0f, 1.0f);
gluSphere(gluNewQuadric(), 0.20, 5, 5);
glPushMatrix(); // Pop back to sun
// Render a moon around Planet 2
glRotatef((rotation*2.0), 0, 1, 0);
glTranslatef(1.5, 0, 0);
glScalef(0.3, 0.3, 0.3);
glColor3f(0.0f, 0.0f, 1.0f);
gluSphere(gluNewQuadric(), 0.20, 20, 20);
glPopMatrix(); // Pop to planet 2
glPushMatrix(); // Push for default matrix
// Render a SECOND moon around Planet 2
glRotatef((rotation * 2), 0, 0, 1);
glTranslatef(1.5, 0, 0);
glScalef(0.3, 0.3, 0.3);
glColor3f(0.0f, 0.0f, 1.0f);
gluSphere(gluNewQuadric(), 0.20, 20, 20);
glPopMatrix();
//glPopMatrix();
glPopMatrix(); // Go back to sun!
glPushMatrix();
glTranslatef(2, 2, 2);
glColor3f(1, 0, 0);
gluSphere(gluNewQuadric(), 0.5, 20, 20);
glPopMatrix();
// End render geometry --------------------------------------
// Render text, should be last object rendered.
renderTextOutput();
// Swap buffers, after all objects are rendered.
glutSwapBuffers();
}
// Handles the resize of the window. If the window changes size the perspective matrix requires re-calculation to match new window size.
void Scene::resize(int w, int h)
{
width = w;
height = h;
// Prevent a divide by zero, when window is too short
// (you cant make a window of zero width).
if (h == 0)
h = 1;
float ratio = (float)w / (float)h;
fov = 45.0f;
nearPlane = 0.1f;
farPlane = 100.0f;
// Use the Projection Matrix
glMatrixMode(GL_PROJECTION);
// Reset Matrix
glLoadIdentity();
// Set the viewport to be the entire window
glViewport(0, 0, w, h);
// Set the correct perspective.
gluPerspective(fov, ratio, nearPlane, farPlane);
// Get Back to the Modelview
glMatrixMode(GL_MODELVIEW);
}
// Calculates FPS
void Scene::calculateFPS()
{
frame++;
time = glutGet(GLUT_ELAPSED_TIME);
if (time - timebase > 1000) {
sprintf_s(fps, "FPS: %4.2f", frame*1000.0 / (time - timebase));
timebase = time;
frame = 0;
}
}
// Compiles standard output text including FPS and current mouse position.
void Scene::renderTextOutput()
{
// Render current mouse position and frames per second.
sprintf_s(mouseText, "Mouse: %i, %i", input->getMouseX(), input->getMouseY());
displayText(-1.f, 0.96f, 1.f, 0.f, 0.f, mouseText);
displayText(-1.f, 0.90f, 1.f, 0.f, 0.f, fps);
}
// Renders text to screen. Must be called last in render function (before swap buffers)
void Scene::displayText(float x, float y, float r, float g, float b, char* string) {
// Get Lenth of string
int j = strlen(string);
// Swap to 2D rendering
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-1.0, 1.0, -1.0, 1.0, 5, 100);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
// Orthographic lookAt (along the z-axis).
gluLookAt(0.0f, 0.0f, 10.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);
// Set text colour and position.
glColor3f(r, g, b);
glRasterPos2f(x, y);
// Render text.
for (int i = 0; i < j; i++) {
glutBitmapCharacter(GLUT_BITMAP_HELVETICA_12, string[i]);
}
// Reset colour to white.
glColor3f(1.f, 1.f, 1.f);
// Swap back to 3D rendering.
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(fov, ((float)width/(float)height), nearPlane, farPlane);
glMatrixMode(GL_MODELVIEW);
}
Updated sun code :
// Render sun
glTranslatef(0.5, 0.5, -0.5);
glColor3f(1.0f, 0.0f, 0.0f);
gluSphere(gluNewQuadric(), 0.20, 20, 20);
glPushMatrix(); // Push for default matrix
// Render Planet 1
glRotatef(rotation, 0.5, 0.5, 0);
glTranslatef(0, 0, 1);
glScalef(1, 1, 1);
glColor3f(0.0f, 2.0f, 0.0f);
gluSphere(gluNewQuadric(), 0.20, 10, 10);
glPopMatrix(); // Pop off stack back to sun matrix
glPushMatrix(); // Push for default matrix
Found out i was missing a OpenGL setting
glEnable(GL_COLOR_MATERIAL);
Inserted at the start of Scene
Try to end glEnable(GL_TEXTURE_2D); with glDisable(GL_TEXTURE_2D); after you render sun.
If problem appeared after you added skybox. Check if vertices are in right order.
In many demoscene productions you can see the effect of flashing white screen when percussion beat happens (https://www.youtube.com/watch?v=2SbGffUzHSs). I have coded such effect and in works fine. Code of fading function (it ie executed in the render() function):
void fade()
{
glLoadIdentity();
glTranslatef (0.0f, 0.0f, -5.0f);
glPolygonMode(GL_FRONT, GL_FILL);
glPolygonMode(GL_BACK, GL_FILL);
glDisable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc (GL_SRC_ALPHA, GL_ONE);
if (alpha <= 1)
{
glColor4f(1.0, 1.0, 1.0, alpha);
glBegin(GL_QUADS);
glVertex3f(-1.0f, -1.0f, 1.0f);
glVertex3f( 1.0f, -1.0f, 1.0f);
glVertex3f( 1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glEnd();
alpha += 0.0025;
}
else
{
glColor4f(1.0, 1.0, 1.0, alpha_inv);
glBegin(GL_QUADS);
glVertex3f(-1.0f, -1.0f, 1.0f);
glVertex3f( 1.0f, -1.0f, 1.0f);
glVertex3f( 1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glEnd();
alpha_inv -= 0.0025;
}
glDisable(GL_BLEND);
glEnable(GL_TEXTURE_2D);
return;
}
I have two issues:
I need some kind of parameter for white flash duration control (ie. 1st flash lasts 1 second, 2 flash lasts only 0,25 second)
The effect has to have the same speed on each computer (slow and fast).
What can I do in the code above to achieve it?
I want to have 2 squares under each other centered in an openGL scene.
I want it like this: https://image.prntscr.com/image/776a14cd345047a1985072e0cf279ceb.png
How can I do this, with glVertex and glColor?
Thanks
Something like this:
void draw() {
glBegin(GL_QUADS);
glColor3f(0.0f, 0.0f, 0.0f);
glVertex2f(-1.0f, -1.0f);
glVertex2f( 1.0f, -1.0f);
glVertex2f( 1.0f, 1.0f);
glVertex2f(-1.0f, 1.0f);
glColor3f(1.0f, 1.0f, 1.0f);
glVertex2f(-0.5f, 0.8f);
glVertex2f( 0.8f, 0.8f);
glVertex2f( 0.8f, 0.0f);
glVertex2f(-0.5f, 0.0f);
glVertex2f(-0.3f, 0.0f);
glVertex2f( 0.6f, 0.0f);
glVertex2f( 0.6f,-0.6f);
glVertex2f(-0.3f,-0.6f);
glEnd();
}
It was one of my better eye-balling jobs. Output (left is mine, bottom-right is yours):
Note that I am drawing a full-screen black quad instead of what one would usually do (glClearColor(0.0f, 0.0f, 0.0f); then glClear(GL_COLOR_BUFFER_BIT);) since you asked specifically in terms of glColor and glVertex.
I am pretty new to OpenGL and have run into a problem trying to render a skybox.
This picture illustrates the issue fairly well.
The sides of the skybox do not show up, and when I view an edge (like in the pic),
it just looks like the images are rendered right next to each other, instead of as
different sides of a cube.
void display ( void ) // Create The Display Function
{
glPushMatrix();
glDepthMask(0);
/* replace this code with your height field implementation */
/* you may also want to precede it with your rotation/translation/scaling */
/* Clear buffers */
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt( 0.0, 0.0, 0.0, // eye position
0.1, 0.0, 0.1, // camera direction
0.0, 1.0, 0.0); // up direction
glPushAttrib(GL_ENABLE_BIT);
glEnable(GL_TEXTURE_2D);
glDisable(GL_DEPTH_TEST);
glDisable(GL_LIGHTING);
glDisable(GL_BLEND);
glColor4f(1.0, 1.0, 1.0, 1.0);
/*!!!!!!!!!!!!!! FRONT FACE !!!!!!!!!!!!!!!*/
glBindTexture(GL_TEXTURE_2D,frontTextureId); // select which texture to use
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( 0.5f, 0.5f, -0.5f );
glTexCoord2f(1, 0); glVertex3f( -0.5f, 0.5f, -0.5f );
glTexCoord2f(1, 1); glVertex3f( -0.5f, -0.5f, -0.5f );
glTexCoord2f(0, 1); glVertex3f( 0.5f, -0.5f, -0.5f );
glEnd();
/*!!!!!!!!!!!!!! LEFT FACE !!!!!!!!!!!!!!!*/
glBindTexture(GL_TEXTURE_2D, leftTextureId); // select which texture to use
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( 0.5f, 0.5f, 0.5f );
glTexCoord2f(1, 0); glVertex3f( 0.5f, 0.5f, -0.5f );
glTexCoord2f(1, 1); glVertex3f( 0.5f, -0.5f, -0.5f );
glTexCoord2f(0, 1); glVertex3f( 0.5f, -0.5f, 0.5f );
glEnd();
/*!!!!!!!!!!!!!! RIGHT FACE !!!!!!!!!!!!!!!*/
glBindTexture(GL_TEXTURE_2D, rightTextureId); // select which texture to use
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( -0.5f, 0.5f, -0.5f );
glTexCoord2f(1, 0); glVertex3f( -0.5f, 0.5f, 0.5f );
glTexCoord2f(1, 1); glVertex3f( -0.5f, -0.5f, 0.5f );
glTexCoord2f(0, 1); glVertex3f( -0.5f, -0.5f, -0.5f );
glEnd();
/*!!!!!!!!!!!!!! BACK FACE !!!!!!!!!!!!!!!*/
glBindTexture(GL_TEXTURE_2D, backTextureId); // select which texture to use
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( -0.5f, 0.5f, 0.5f );
glTexCoord2f(1, 0); glVertex3f( 0.5f, 0.5f, 0.5f );
glTexCoord2f(1, 1); glVertex3f( 0.5f, -0.5f, 0.5f );
glTexCoord2f(0, 1); glVertex3f( -0.5f, -0.5f, 0.5f );
glEnd();
/*!!!!!!!!!!!!!! TOP FACE !!!!!!!!!!!!!!!*/
glBindTexture(GL_TEXTURE_2D, upTextureId); // select which texture to use
glBegin(GL_QUADS);
glTexCoord2f(0, 1); glVertex3f( -0.5f, 0.5f, -0.5f );
glTexCoord2f(0, 0); glVertex3f( -0.5f, 0.5f, 0.5f );
glTexCoord2f(1, 0); glVertex3f( 0.5f, 0.5f, 0.5f );
glTexCoord2f(1, 1); glVertex3f( 0.5f, 0.5f, -0.5f );
glEnd();
/*!!!!!!!!!!!!!! BOTTOM FACE !!!!!!!!!!!!!!!*/
glBindTexture(GL_TEXTURE_2D, downTextureId); // select which texture to use
glBegin(GL_QUADS);
glTexCoord2f(0, 0); glVertex3f( -0.5f, -0.5f, -0.5f );
glTexCoord2f(0, 1); glVertex3f( -0.5f, -0.5f, 0.5f );
glTexCoord2f(1, 1); glVertex3f( 0.5f, -0.5f, 0.5f );
glTexCoord2f(1, 0); glVertex3f( 0.5f, -0.5f, -0.5f );
glEnd();
/*!!!!!!!!!!!!!! end of drawing of a textured quad !!!!!!!!!!!!!!!*/
glPopAttrib();
glPopMatrix();
/* Swap buffers, so one we just drew is displayed */
glutSwapBuffers();
}
I feel like I am missing something basic here, but I am not sure what. The code is
more or less verbatim from the tutorial site (http://sidvind.com/wiki/Skybox_tutorial).
The code was compiled with g++ 4.5.2 on Ubuntu Linux, but the same problem arises under
visual studio as well.
I should state, as well, that the numbers used in the code above are the values that
produced the linked picture.
Your textures need to form a seamless join across cube edges. In the screenshot you've supplied, these images don't form a seamless join (look at the sky).
Also check your projection matrix - are you setting a perspective transform?
To set up a perspective projection (the most common for 3D apps):
glMatrixMode(GL_PROJECTION); // switch to projection matrix
glLoadIdentity(); // reset projection
gluPerspective(90.0,4.0/3.0,0.01,10.0); // 90deg FOV, 4:3 aspect ratio, 0.01 near clip plane, 10.0 far clip plane
glMatrixMode(GL_MODELVIEW); // back to model matrix
It looks to me like the texture on the right ought to be on the left of the left image. So I'd guess you are texturing the wrong sides of your cube.
I want to render outline font near playing area, but these two parts are in conflict. If I render only outline font, it's ok. When I render also playing area, textures of cubes have defect and light is changed also. When I render only playing area, it's ok. Here are some pictures:
http://img.obrazok.com/Untitled.usdh.png
Outline font part:
//Display-lists
GLuint fontBase;
GLYPHMETRICSFLOAT gmf[256];
//********************************
//3D Font
//********************************
GLvoid BuildFont(GLvoid) // Build Our Bitmap Font
{
HFONT font; // Windows Font ID
fontBase = glGenLists(256); // Storage For 256 Characters
font = CreateFont( -12, // Height Of Font
0, // Width Of Font
0, // Angle Of Escapement
0, // Orientation Angle
FW_BOLD, // Font Weight
FALSE, // Italic
FALSE, // Underline
FALSE, // Strikeout
ANSI_CHARSET, // Character Set Identifier
OUT_TT_PRECIS, // Output Precision
CLIP_DEFAULT_PRECIS, // Clipping Precision
ANTIALIASED_QUALITY, // Output Quality
FF_DONTCARE|DEFAULT_PITCH, // Family And Pitch
"Comic Sans MS"); // Font Name
HDC hDC = GetDC(GetActiveWindow());
SelectObject(hDC, font); // Selects The Font We Created
wglUseFontOutlines( hDC, // Select The Current DC
0, // Starting Character
255, // Number Of Display Lists To Build
fontBase, // Starting Display Lists
0.0f, // Deviation From The True Outlines
0.2f, // Font Thickness In The Z Direction
WGL_FONT_POLYGONS, // Use Polygons, Not Lines
gmf); // Address Of Buffer To Recieve Data
}
GLvoid KillFont(GLvoid) // Delete The Font
{
glDeleteLists(fontBase, 256); // Delete All 256 Characters
}
void printString(const char *string, float x, float y, float z) // Custom GL "Print" Routine
{
float length=0; // Used To Find The Length Of The Text
for (unsigned int loop=0;loop<(strlen(string));loop++) // Loop To Find Text Length
{
length+=gmf[string[loop]].gmfCellIncX; // Increase Length By Each Characters Width
}
glPushMatrix();
glRotatef(90,0.0,0.0,1.0);
glRotatef(90,1.0,0.0,0.0);
glTranslatef(x,y,z);
glPushAttrib(GL_LIST_BIT); // Pushes The Display List Bits
glListBase(fontBase); // Sets The Base Character to 0
glCallLists(strlen(string), GL_UNSIGNED_BYTE, string); // Draws The Display List Text
glPopAttrib(); // Pops The Display List Bits
glPopMatrix();
}
Render playing area:
//Display-lists
GLuint ls_mapWalls;
void renderWalls() {
for (int x = 0; x < mapSize; x++) {
for (int y = 0; y < mapSize; y++) {
glPushMatrix();
glTranslatef(x*2.0f,y*2.0f,0.0f);
if (map[x][y] == 'X') {
renderWall();
}
glPopMatrix();
}
}
}
void renderWall() {
glPushMatrix();
renderTexturedCube(1); //1 or 2
glPopMatrix();
}
void renderTexturedCube(int color) {
glEnable(GL_TEXTURE_2D);
switch (color) {
case 1 :
//normal wall
setMaterialColor(1.0f, 1.0f, 1.0f, 0.2f);
break;
case 2 :
//red wall
setMaterialColor(1.0f, 0.0f, 0.0f, 1.0f);
break;
}
glBindTexture(GL_TEXTURE_2D, texid[0]);
glBegin(GL_QUADS);
// Front Face
glNormal3f(0.0,0.0,1.0);
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, 1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 1.0f);
// Back Face
glNormal3f(0.0,0.0,-1.0);
glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, 1.0f, -1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, 1.0f, -1.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
// Top Face
glNormal3f(0.0,1.0,0.0);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, -1.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, 1.0f, 1.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, 1.0f, 1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, -1.0f);
// Bottom Face
glNormal3f(0.0,-1.0,0.0);
glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 1.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);
// Right face
glNormal3f(1.0,0.0,0.0);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, -1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, 1.0f, 1.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 1.0f);
// Left Face
glNormal3f(-1.0,0.0,0.0);
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, -1.0f);
glEnd();
setMaterialColor(1.0f, 1.0f, 1.0f, 1.0f);
glDisable(GL_TEXTURE_2D);
}
Render part:
void render(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
GLdouble ex = vzd*cos(fi)*cos(xi);
GLdouble ey = vzd*sin(fi)*cos(xi);
GLdouble ez = vzd*sin(xi);
gluLookAt( ex, ey, ez, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f );
printString("Dyna Blaster Beta", 10, 10, 10, 1.0, 0.0, 0.0);
glCallList(ls_mapWalls);
glutSwapBuffers();
}
Init part:
bool init(void)
{
//setup OpenGL
glShadeModel(GL_SMOOTH);
glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
glClearDepth(1.0f);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
glClearColor (0.0, 0.0, 0.0, 0.0);
glEnable(GL_CULL_FACE);
//files load
loadMap();
loadTextures();
//next init
ls_mapWalls = glGenLists(1);
glNewList(ls_mapWalls, GL_COMPILE);
renderWalls();
glEndList();
glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 2.0);
GLfloat light_ambient[] = { 0.1, 0.1, 0.1, 1.0 };
GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat light_position[] = { 10.0, 10.0, 10.0, 0.0 };
glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);
glEnable(GL_LIGHT0);
glEnable(GL_LIGHTING);
BuildFont();
fi = 0.385f; xi = 0.515f; vzd = 69.2f;
return true;
}
If you have some question or want see another part of code, just ask. Thank you.
The documentation for wglUseFontOutlines at MSDN says this:
With WGL_FONT_POLYGONS, the created display lists call glFrontFace( GL_CW )
or glFrontFace( GL_CCW ); thus the current front-face value might be altered.
OpenGL defults to GL_CCW; so chances are, if you set it back with
glFrontFace( GL_CCW );
after drawing the text, your playing area will render correctly.