OpenGL 2d texture render issue - c++

I am trying to load and draw a 2d texture using OpenGL with GLFW and SOIL. I have this code, but I only get one solid color (which seems to come from the texture).
I have tested whether the .png loads with an example that came with SOIL, and it worked fine so there has to be some issue in my code.
This is my code:
#include <cstdio>
#include "GL/glfw.h"
#include "SOIL.h"
// function declarations
void drawscene();
void idlefunc();
void updatedisplay();
// global data
GLuint texture; // our example texture
int main(int argc, char **argv) {
if (!glfwInit()) {
fprintf(stderr, "Failed to initialize GLFW\n");
return 1;
}
if (!glfwOpenWindow(640, 480, 0, 0, 0, 0, 16, 0, GLFW_WINDOW)) {
fprintf(stderr, "Failed to open GLFW window\n");
return 1;
}
// enable vsync (if available)
glfwSwapInterval(1);
// load textures
texture = SOIL_load_OGL_texture(
"tex.png",
SOIL_LOAD_AUTO,
SOIL_CREATE_NEW_ID,
SOIL_FLAG_POWER_OF_TWO | SOIL_FLAG_MIPMAPS | SOIL_FLAG_DDS_LOAD_DIRECT
);
// check for an error during the texture loading
if (!texture) {
printf("SOIL loading error: '%s'\n", SOIL_last_result());
}
while (glfwGetWindowParam(GLFW_OPENED)) {
idlefunc();
}
// if we get here something went wrong
return 0;
}
// this function gets called every frame
void idlefunc() {
updatedisplay();
drawscene();
}
// set up te display
void updatedisplay() {
int screen_width, screen_height;
glfwGetWindowSize(&screen_width, &screen_height);
if (screen_height <= 0) screen_height = 1;
if (screen_width <= 0) screen_width = 1;
glViewport(0, 0, screen_width, screen_height);
glClearColor(0.02f, 0.02f, 0.02f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
glEnable(GL_TEXTURE_2D);
glDisable(GL_DEPTH_TEST);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, screen_width, screen_height, 0.0, 0.0, 1.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
// displacement trick for exact pixelization
glTranslatef(0.375f, 0.375f, 0.0f);
}
// draw the scene in this function
void drawscene() {
glBindTexture(GL_TEXTURE_2D, texture);
glPushMatrix();
glTranslatef(10.0f, 10.0f, 0);
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 0.0f);
glVertex2f(0.0f, 0.0f);
glTexCoord2f(0.0f, 128.0f);
glVertex2f(0.0f, 128.0f);
glTexCoord2f(128.0f, 128.0f);
glVertex2f(128.0f, 128.0f);
glTexCoord2f(128.0f, 0.0f);
glVertex2f(128.0f, 0.0f);
glEnd();
glPopMatrix();
glfwSwapBuffers();
}

Found the issue (thanks to user786653). No matter the vertex coords, the tex coords are between 0.0 and 1.0. This is the fixed code:
// draw the scene in this function
void drawscene() {
glBindTexture(GL_TEXTURE_2D, texture);
glPushMatrix();
glTranslatef(10.0f, 10.0f, 0);
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 0.0f);
glVertex2f(0.0f, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex2f(0.0f, 128.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex2f(128.0f, 128.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex2f(128.0f, 0.0f);
glEnd();
glPopMatrix();
glfwSwapBuffers();
}

Related

OpenGL texture loading with soil help need

Here is the code. Please help guys
#include <GL/glut.h>
#include <iostream>
#include <math.h>
#include "SOIL.h"
using namespace std;
GLuint texture[1];
int LoadGLTextures()
{
texture[0] = SOIL_load_OGL_texture
(
"NeHe.bmp",
SOIL_LOAD_AUTO,
SOIL_CREATE_NEW_ID,
SOIL_FLAG_INVERT_Y
);
if(texture[0] == 0)
return false;
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
return true;
}
void ChangeSize(int w, int h)
{
if(h == 0)
{
h = 1;
}
float ratio = 1.0f * w/h;
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glViewport(0,0,w,h);
gluPerspective(45,ratio,1,1000);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0.0,0.0,6.0,
0.0,0.0,0.0,
0.0f,1.0f,0.0f);
}
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glBegin(GL_QUADS);
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();
glFlush();
}
void idle(void)
{
glutPostRedisplay();
}
int main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitWindowSize(640,480);
glutInitWindowPosition(10,10);
glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH);
glutCreateWindow("ZC");
glutReshapeFunc(ChangeSize);
glutDisplayFunc(display);
glutIdleFunc(idle);
glEnable(GL_DEPTH_TEST);
glutMainLoop();
}
I dont get errors, but not loading the texture.
You forgot to call LoadGLTextures in your main program. I ran your program with this change:
glEnable(GL_DEPTH_TEST);
LoadGLTextures(); //<-- added this
glutMainLoop();
}
and things worked fine.
I provided my own NeHe.bmp file, since you didn't link to one. It could also fail if your .bmp file is bad in some way.

Texture not displaying in OpenGL

The triangle i drew with OpenGL can't be displayed. When i debug my code it's only the white background appeared. Can anyone help me?
#pragma warning(disable:4996)
#include <Windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <glut.h>
#include <SOIL.h>
const float piOver180 = 0.0174532925f;
float heading;
float xPos;
float zPos;
//declarations
GLuint filter;
GLuint texture[3];
int width = 720;
int height = 540;
void init();
void display();
void drawTriangle();
void reshape(int width, int height);
this is my main function
int main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glutInitWindowSize(width, height);
glutInitWindowPosition(0, 0);
glutCreateWindow("Muzeum");
init();
glutDisplayFunc(display);
glutIdleFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutMainLoop();
}
void init()
{
texture[0] = SOIL_load_OGL_texture
(
"wallpaper.bmp",
SOIL_LOAD_AUTO,
SOIL_CREATE_NEW_ID,
SOIL_FLAG_MIPMAPS | SOIL_FLAG_INVERT_Y | SOIL_FLAG_NTSC_SAFE_RGB | SOIL_FLAG_COMPRESS_TO_DXT
);
texture[1] = texture[2] = texture[0];
if (texture[0] == 0 || texture[1] == 0 || texture[2] == 0)
{
printf("SOIL loading error: '%s'\n", SOIL_last_result());
exit(0);
}
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR);
}
my display function
void display()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glBlendFunc(GL_SRC_ALPHA, GL_ONE);
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClearDepth(1.0);
glEnable(GL_DEPTH_TEST);
GLfloat xTrans = -xPos;
GLfloat yTrans = -walk - 0.25f;
GLfloat zTrans = -zPos;
GLfloat sceneRotY = 360.0f - yRot;
glTranslatef(xTrans, yTrans, zTrans);
drawTriangle();
glFlush();
glutSwapBuffers();
}
where i draw my triangle
void drawTriangle()
{
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glBegin(GL_TRIANGLES);
glNormal3f(0.0f, 0.0f, 1.0f);
glTexCoord2f(-3.0f, 0.0f); glVertex3f(-3.0f, 0.0f, 6.0f);
glTexCoord2f(-3.0f, 0.0f); glVertex3f(-3.0f, 0.0f, 0.0f);
glTexCoord2f(3.0f, 0.0f); glVertex3f(3.0f, 6.0f, 0.0f);
glTexCoord2f(-3.0f, 0.0f); glVertex3f(-3.0f, 0.0f, 6.0f);
glTexCoord2f(3.0f, 0.0f); glVertex3f(-3.0f, 6.0f, 6.0f);
glTexCoord2f(3.0f, 0.0f); glVertex3f(3.0f, 6.0f, 0.0f);
glEnd();
glDisable(GL_TEXTURE_2D);
}
void reshape(int width, int height)
{
glViewport(0, 0, (GLsizei)width, (GLsizei)height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(40.0f, (GLdouble)width / (GLdouble)height, 0.5f, 20.0f);
glMatrixMode(GL_MODELVIEW);
}
What i want to do is a room with texture-mapped, now this is only my floor part.
The main problem is that your geometry is not in your field of view. Your gluPerspective() call sets up a projection transformation with a camera placed on the origin, and pointing in the negative z-direction. With the values for the near and far planes, it will show z-values in the range from -0.5 to -20.0. All the z-values of your geometry are in the range 0.0 to 6.0, so all your geometry is behind the camera.
I tried most of your code, and I got things showing up by adding a translation to the modelview transformation. For example, adding a line after the first two lines of the display() function:
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glTranslatef(0.0f, 0.0f, -10.0f);
A few more things that could get in your way:
No call to glutInit(). I figure you have that in the original code.
GL_LINEAR_MIPMAP_LINEAR is not a legal value for GL_TEXTURE_MAG_FILTER. This must be GL_LINEAR or GL_NEAREST. glGetError() is your friend!
Fortunately you didn't enable blending, because your glBlendFunc() call, in combination with a white clear color, would prevent anything from being drawn. You would add to white, and that whole whiter than white thing only works in detergent commercials. ;)
Clearing alpha to 1.0, as you do with the last argument of glClearColor() is quite unusual. Doesn't really hurt for now, since you only use an RGB framebuffer, and do not blend with destination alpha.
glFlush() before glutSwapBuffers() is redundant, and only hurts performance.

Unable to render RGB frames in openGL using textures

I'm trying to render a set of 200 RGB frames. For doing the same i'm creating a texture of height 416 and width 240. However i just get a black screen with the print statements working in the background.
Below is my code:
#include <stdio.h>
#include <stdlib.h>
#include "glew.h"
#include "glfw.h"
#include "glaux.h"
int index;
AUX_RGBImageRec texture1;
GLuint texture;
unsigned long long pos;
unsigned char *guibuffer;
HDC hDC = NULL;
void initGL(void)
{
int maxSz;
int maxwidth = 416;
int maxheight = 240;
if( !glfwInit() )
{
exit( EXIT_FAILURE );
}
// if( !glfwOpenWindow(4096, 2118, 0,0,0,0,0,0, GLFW_WINDOW ) )
if( !glfwOpenWindow(maxwidth, maxheight, 0,0,0,0,0,0, GLFW_WINDOW ) ) //GLFW_FULLSCREEN
{
glfwTerminate();
exit( EXIT_FAILURE );
}
glfwSetWindowTitle("sample");
glGetIntegerv(GL_MAX_TEXTURE_SIZE,&maxSz);
glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // This Will Clear The Background Color To Black
glClearDepth(1.0); // Enables Clearing Of The Depth Buffer
glDepthFunc(GL_LESS); // The Type Of Depth Test To Do
glEnable(GL_DEPTH_TEST); // Enables Depth Testing
glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading
glMatrixMode(GL_PROJECTION);
//glLoadIdentity();
hDC= wglGetCurrentDC();
#if 1
{ // TSS
HWND hCurrentWindow = GetActiveWindow();
char szTitle[256]="sample";
//SetWindowText(hCurrentWindow,szTitle );
// SetWindowLongA (hCurrentWindow , GWL_STYLE, (GetWindowLongA (hCurrentWindow , GWL_STYLE) & ~(WS_CAPTION)));
SetWindowLongA (hCurrentWindow, GWL_STYLE, (WS_VISIBLE));
}
#endif
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
}
int GL_Disply()
{
FILE *fptr=fopen("E:\\myRGB.rgb","rb");
fseek(fptr,pos,SEEK_SET);
fread(guibuffer,sizeof(unsigned char),sizeof(unsigned char)*416*240*3,fptr);
pos+=416*240*3;
texture1.sizeX =416;
texture1.sizeY =240;
texture1.data = guibuffer;
glDepthFunc(GL_ALWAYS);
glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
glDisable(GL_LIGHTING);
glEnable(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, texture1.sizeX, texture1.sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
glBegin(GL_QUADS);
//glNormal3f( 0.0f, 0.0f, 0.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, -1.0f, 0.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, -1.0f, 0.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, 1.0f, 0.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, 1.0f, 0.0f);
glEnd();
glDisable(GL_BLEND);
glEnable(GL_DEPTH_TEST);
// Swap front and back rendering buffers
glfwSwapBuffers();
glDeleteTextures(1, &texture);
}
int main(int argc, char *argv[])
{
initGL(); // GL initialization
/* CPU memory allocation using C - malloc */
guibuffer=(unsigned char*)malloc(sizeof(unsigned char)*416*240*3);
for(index=0;index<200;index++)
{
printf("frame %d displayed....\r",index);
GL_Disply();
}
return 0;
}
Can anyone please tell me where i'm going wrong?
You are not passing data (last parameter) to the glTexImage2D function. I guess you would want to pass data readed from your E:\myRGB.rgb file.
It may have something to do with the matrix stack. I think you want to be in glMatrixMode (GL_MODELVIEW) when you draw stuff, not GL_PROJECTION, and you may need to set up your matrices correctly. Though, glMatrixMode, glBegin, glEnd, glTexCoord, glVertex3f, is the old fixed function way of rendering. Using shaders is the modern way of rendering with OpenGL.

Black screen in LWJGL

I'm currently porting a game of which the code is very obfuscated due to porting from C to Java.
My problem is that some users report a black screen and no other problems (sound is working fine e.g.), with no errors showing a problem. On my pc it runs fine, and it makes for a hell of debugging.
I was wondering if anyone can post a (list of) reason(s) this might be occurring. I've read somewhere one of the issues could be using a 32 bits Java on a 64 bits system.
My code below, also opensourced at: https://code.google.com/p/jake2t/
private void renderSideBySide() {
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, sbsFboId);
// Render side by side
glPushAttrib(GL_ALL_ATTRIB_BITS);
glPushMatrix();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0, width, 0, height);
glMatrixMode (GL_MODELVIEW);
glLoadIdentity ();
glViewport(0,0,width,height);
glClearColor(0.0f, 0.0f, 1.0f, 0.0f);
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glDisable(GL_DEPTH_TEST);
glDisable(GL_LIGHTING);
glDisable(GL_BLEND);
glDisable(GL_ALPHA_TEST);
glDisable(GL_CULL_FACE);
int shaderId = sbsShader.getId();
glDisable(GL_TEXTURE_2D);
ARBShaderObjects.glUseProgramObjectARB(shaderId);
if (postFboTextureLocation[0] < 0) {
postFboTextureLocation[0] = ARBShaderObjects.glGetUniformLocationARB(shaderId, "leftTexture");
}
if (postFboTextureLocation[1] < 0) {
postFboTextureLocation[1] = ARBShaderObjects.glGetUniformLocationARB(shaderId, "rightTexture");
}
if (postFboDepthTextureLocation[0] < 0) {
postFboDepthTextureLocation[0] = ARBShaderObjects.glGetUniformLocationARB(shaderId, "leftDepthTexture");
}
if (postFboDepthTextureLocation[1] < 0) {
postFboDepthTextureLocation[1] = ARBShaderObjects.glGetUniformLocationARB(shaderId, "rightDepthTexture");
}
// Load the images with the colors and the depth values
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, postFboTextureId[0]);
ARBShaderObjects.glUniform1iARB(postFboTextureLocation[0], 0);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, postFboTextureId[1]);
ARBShaderObjects.glUniform1iARB(postFboTextureLocation[1], 1);
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, postFboDepthTexture[0]);
ARBShaderObjects.glUniform1iARB(postFboDepthTextureLocation[0], 2);
glActiveTexture(GL_TEXTURE3);
glBindTexture(GL_TEXTURE_2D, postFboDepthTexture[1]);
ARBShaderObjects.glUniform1iARB(postFboDepthTextureLocation[1], 3);
glBegin (GL_QUADS);
glTexCoord2f(0.0f, 0.0f);
glVertex2i (0, 0);
glTexCoord2f(1.0f, 0.0f);
glVertex2i (width, 0);
glTexCoord2f(1.0f, 1.0f);
glVertex2i (width, height);
glTexCoord2f(0.0f, 1.0f);
glVertex2i (0, height);
glEnd();
ARBShaderObjects.glUseProgramObjectARB(0);
// Rendering with warping
glPopMatrix();
glPopAttrib();
unbindFBO();
}
public void drawPostFBOs() {
renderSideBySide();
glPushAttrib(GL_ALL_ATTRIB_BITS);
glPushMatrix();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0, width, 0, height);
glMatrixMode (GL_MODELVIEW);
glLoadIdentity ();
glViewport(0,0,width,height);
glClearColor(0.0f, 0.0f, 1.0f, 0.0f);
glClear (GL_COLOR_BUFFER_BIT);
glDisable(GL_DEPTH_TEST);
glDisable(GL_LIGHTING);
glDisable(GL_BLEND);
glDisable(GL_ALPHA_TEST);
glDisable(GL_CULL_FACE);
glDisable(GL_TEXTURE_2D);
int shaderId = riftShader.getId();
ARBShaderObjects.glUseProgramObjectARB(shaderId);
if (sbsFboTextureLocation < 0) {
sbsFboTextureLocation = ARBShaderObjects.glGetUniformLocationARB(shaderId, "tex");
}
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, sbsFboTextureId);
ARBShaderObjects.glUniform1iARB(sbsFboTextureLocation, 0);
glBegin (GL_QUADS);
glTexCoord2f(0.0f, 0.0f);
glVertex2i (0, 0);
glTexCoord2f(1.0f, 0.0f);
glVertex2i (width, 0);
glTexCoord2f(1.0f, 1.0f);
glVertex2i (width, height);
glTexCoord2f(0.0f, 1.0f);
glVertex2i (0, height);
glEnd();
ARBShaderObjects.glUseProgramObjectARB(0);
glPopMatrix();
glPopAttrib();
}
The common problems that OpenGL 3+ programmer doesn't consider when coding are:
OpenGL Extensions
use of ARB and EXT extension.
use of correct OGL extension.
use multiple implementation of different OGL extensions. Here is an example using C++:
#ifndef _MESA_INVERT_
/*** ... some codes here ... ***/
#else
/*** ... alt some codes here ... ***/
#endif
Check if the video card support the following extension using:
glxinfo - Linux and MacOS X based system.
glview - Windows based system.

OpenGL Plane not showing up

I'm making a particle fountain in openGL, I have the particles functioning properly. I decided to add a plane to make it look like they are bouncing off from it. What I'm trying to get is something like this
Unfortunately what I'm getting is this
the plain doesn't seem to be appearing at all. I tried messing with the co-ordinates and that doesn't seem to do anything. This is the image I'm using as the texture, it's a 256 X 256 24bit bmp.
I load the texture in the init function, then call it before I render the particles in the following function
void Load_Plane(){
glEnable(GL_BLEND);
glBlendFunc(GL_ONE_MINUS_SRC_ALPHA, GL_SRC_ALPHA);
glColor4f(0.0f, 0.2f, 0.2f, 0.5f);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, txPlane);
glBegin(GL_QUADS);
glNormal3f(-10.0f, 0.0f, -10.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(-10.0f, 0.0f, 10.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f( 10.0f, 0.0f, 10.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f( 10.0f, 0.0f, -10.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(-10.0f, 0.0f, -10.0f);
glEnd();
}
full code
// particle_fountain.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include<stdlib.h>
#include <stdio.h>
#include<Windows.h>
#include <time.h>
#include <GL\glut.h>
#include<GL\GLU.h>
#define MAX_PARTICLES 200 //max number of particles
#define MAX_BOUNCE_COUNT 5 //number of times a particle should bounce
#define MAX_PARTICLE_AGE 95
//Colours
float R = 0.8f;
float G = 0.2f;
float B = 0.0f;
float cR = 0.001f;
float cG = 0.002f;
float cB = 0.003f;
float Size = 0.02f; //size for points
GLuint txParticle;
GLuint txPlane;
struct PARTICLE {
float X,Y,Z; // Current position
float sX,sY,sZ; // Current Speed/Movement
float tX,tY,tZ; // Target Speed/Movement
float R,B,G; // Particle Colour
bool Active; // Is particle Active
int Age; // Age of the particle
int MaxAge; // Maximum Age before particle dies
int BounceCount;
} Particles[MAX_PARTICLES];
void Init_Particles();
void Activate_Particles();
void Adjust_Particles();
void Render_Particles();
bool LoadBitmapTexture(char * FileName, GLuint &texid);
void timer(int extra);
void Load_Plane();
void DrawGLscene();
void Reshape(GLsizei w, GLsizei h);
int main(int argc, char** argv){
glutInit(&argc,argv);
glutInitDisplayMode( GLUT_RGBA| GLUT_DOUBLE );
glutInitWindowSize( 640, 480 );
glutCreateWindow("Particle fountain");
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -1.0, 1.0, 1.0, 10.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, -0.9, -3.0);
Init_Particles();
glutDisplayFunc(DrawGLscene);
glutTimerFunc(0, timer, 0);
glutMainLoop();
}
void timer(int extra)
{
glutPostRedisplay();
glutTimerFunc(20, timer, 0);
}
void Load_Plane(){
glEnable(GL_BLEND);
glBlendFunc(GL_ONE_MINUS_SRC_ALPHA, GL_SRC_ALPHA);
glColor4f(0.0f, 0.2f, 0.2f, 0.5f);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, txPlane);
glBegin(GL_QUADS);
glNormal3f(-10.0f, 0.0f, -10.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(-10.0f, 0.0f, 10.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f( 10.0f, 0.0f, 10.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f( 10.0f, 0.0f, -10.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(-10.0f, 0.0f, -10.0f);
glEnd();
}
void DrawGLscene(){
Load_Plane();
glPushMatrix();
glScalef(1.0f, -1.0f, 1.0f);
Render_Particles();
glPopMatrix();
Render_Particles();
}
void Init_Particles(){
LoadBitmapTexture("./Particle.bmp", txParticle); //load the particle texture
LoadBitmapTexture("./Plain.bmp",txPlane); //load the plain texture
int p;
srand((int)time(NULL));
for(p=0; p<MAX_PARTICLES; p++){
Particles[p].Active = FALSE;
Particles[p].tX = 0.0f;
Particles[p].tY = -0.1f;
Particles[p].tZ = 0.0f;
}
}
void Activate_Particles(){
int p;
for(p=0; p<MAX_PARTICLES; p++){
if(!Particles[p].Active){
// Start the particle at 0,0,0 origin
Particles[p].X = 0.0f;
Particles[p].Y = 0.0f;
Particles[p].Z = 0.0f;
// The following lines set a random speed value
Particles[p].sX = (((float)((rand() % 100) + 1)) /
1000.0f) - 0.05f;
Particles[p].sY = (((float)((rand() % 100) + 50)) /
500.0f);
Particles[p].sZ = (((float)((rand() % 100) + 1)) /
1000.0f) - 0.05f;
// We also activate the particle
Particles[p].Active = true;
// Set it's Age to zero
Particles[p].Age = 0;
// We also assign a max age to the particles
Particles[p].MaxAge = MAX_PARTICLE_AGE;
// We Also reset the bouncecount to zero
Particles[p].BounceCount = 0;
//Adding the colours
Particles[p].R = R;
Particles[p].G = G;
Particles[p].B = B;
R+=cR;
G+=cG;
B+=cB;
if(R>1.0f){R=1.0f; cR=-cR;}
if(R<0.0f){R=0.0f; cR=-cR;}
if(G>1.0f){G=1.0f; cG=-cG;}
if(G<0.0f){G=0.0f; cG=-cG;}
if(B>1.0f){B=1.0f; cB=-cB;}
if(B<0.0f){B=0.0f; cB=-cB;}
return;
}
}
}
void Adjust_Particles(){
int p;
for(p=0; p<MAX_PARTICLES; p++){
// We move the speed towards the target speed by 1/20 (5%)
Particles[p].sX+= (Particles[p].tX - Particles[p].sX) / 20.0f;
Particles[p].sY+= (Particles[p].tY - Particles[p].sY) / 20.0f;
Particles[p].sZ+= (Particles[p].tZ - Particles[p].sZ) / 20.0f;
// Then we adjust the position of
// the particle by the new speed
Particles[p].X+= Particles[p].sX;
Particles[p].Y+= Particles[p].sY;
Particles[p].Z+= Particles[p].sZ;
// Now for the bounce code.
if(Particles[p].Y < 0.0f){
Particles[p].Y = 0.0f;
Particles[p].sY = -Particles[p].sY;
Particles[p].BounceCount++;
if(Particles[p].BounceCount > MAX_BOUNCE_COUNT){
Particles[p].Active = FALSE;
}
}
// And finally the age check
Particles[p].Age++;
if(Particles[p].Age > Particles[p].MaxAge){
Particles[p].Active = FALSE;
}
}
}
void Render_Particles(){
Activate_Particles();
Adjust_Particles();
glClear( GL_COLOR_BUFFER_BIT );
int p;
// Enable textures and bind our particle texture
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, txParticle);
// Disable Depth testing.
glDisable(GL_DEPTH_TEST);
// Enable blending
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_COLOR,GL_ONE);
for(p=0; p<MAX_PARTICLES; p++){
if(Particles[p].Active){
glColor4f(Particles[p].R,
Particles[p].G,
Particles[p].B, 1.0f);
glPushMatrix();
glTranslatef(Particles[p].X,
Particles[p].Y,
Particles[p].Z);
glBegin(GL_QUADS);
glNormal3f(0.0f, 0.0f, 1.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(-Size, -Size, 0.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(Size, -Size, 0.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(Size, Size, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(-Size, Size, 0.0f);
glEnd();
glPopMatrix();
}
}
glEnable(GL_DEPTH_TEST);
glutSwapBuffers();
}
bool LoadBitmapTexture(char * FileName, GLuint &texid){
HBITMAP hBMP; // Handle Of The Bitmap
BITMAP BMP; // Bitmap Structure
glGenTextures(1, &texid); // Create The Texture
hBMP=(HBITMAP)LoadImage(GetModuleHandle(NULL),
FileName,
IMAGE_BITMAP, 0, 0,
LR_CREATEDIBSECTION | LR_LOADFROMFILE
);
if (!hBMP) // Does The Bitmap Exist?
return FALSE; // If Not Return False
GetObject(hBMP, sizeof(BMP), &BMP); // Get The Object
// hBMP: Handle To Graphics Object
// sizeof(BMP): Size Of Buffer For Object Information
// &BMP: Buffer For Object Information
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
// Pixel Storage Mode (Word Alignment / 4 Bytes)
// Typical Texture Generation Using Data From The Bitmap
glBindTexture(GL_TEXTURE_2D, texid);// Bind To The Texture ID
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_LINEAR); // Linear Min Filter
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
GL_LINEAR); // Linear Mag Filter
glTexImage2D(GL_TEXTURE_2D, 0, 3, BMP.bmWidth, BMP.bmHeight,
0, GL_BGR_EXT, GL_UNSIGNED_BYTE, BMP.bmBits);
DeleteObject(hBMP); // Delete The Object
return TRUE; // Loading Was Successful
}
It could be that you're not clearing the depth buffer.
It doesn't affect any of the particles because you are disabling depth test when you render them, but when you render the plane, depth test is enabled, and since the depth buffer has not been cleared it has a spaz and doesn't render the plane.
Do
glClear(GL_DEPTH_BUFFER_BIT);
before you render the plane to clear the depth buffer.
EDIT:
This must be it-
You are calling
glClear(GL_COLOR_BUFFER_BIT);
after you render the plane. Look at your DrawGLScene function:
Load_Plane(); // you are drawing the plane here
glPushMatrix();
glScalef(1.0f, -1.0f, 1.0f);
Render_Particles(); // this function calls "glClear( GL_COLOR_BUFFER_BIT );"
// so anything that you rendered before is now removed.
glPopMatrix();
Render_Particles(); // same goes for here.
The solution would be to remove the call to glClear from your Render_Particles function,
and add it to the top of DrawGLScene:
(New DrawGLScene Code)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
Load_Plane();
glPushMatrix();
glScalef(1.0f, -1.0f, 1.0f);
Render_Particles();
glPopMatrix();
Render_Particles();
EDIT #2:
You're calling glutSwapBuffers in the Render_Particles function.
Don't call it there. Call it at the end of DrawGLScene: