I'm trying to draw some texture with CAOpenGLLayer, but receiving GL_INVALID_OPERATION when i try to call glTexSubImage2d. According to this document : http://www.opengl.org/sdk/docs/man/xhtml/glTexSubImage2D.xml it's one of the errors described there. But seems i'm not breaking any rule described there and i don't understand what i'm doing wrong. Here is a code that i'm trying to run:
- (CGLContextObj)copyCGLContextForPixelFormat:(CGLPixelFormatObj)pixelFormat
{
uint32_t plugin_width = 32, plugin_height = 32;
texture_data = new uint8_t[plugin_width * plugin_height * 4];
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glScalef(1.0f, -1.0f, 1.0f);
glOrtho(0, plugin_width , 0, plugin_height , -1.0, 1.0);
glActiveTexture(GL_TEXTURE0);
glEnable(GL_TEXTURE_RECTANGLE_EXT);
glGenTextures(1, &textureName);
glBindTexture(GL_TEXTURE_RECTANGLE_EXT, textureName);
glTextureRangeAPPLE(GL_TEXTURE_RECTANGLE_EXT, plugin_width * plugin_height * 4, texture_data);
glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_STORAGE_HINT_APPLE , GL_STORAGE_SHARED_APPLE);
glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glTexImage2D(GL_TEXTURE_RECTANGLE_EXT, 0, GL_RGBA, plugin_width, plugin_height, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8, texture_data);
glBindTexture(GL_TEXTURE_RECTANGLE_EXT, 0);
return [super copyCGLContextForPixelFormat:pixelFormat];
}
- (void)drawInCGLContext:(CGLContextObj)ctx pixelFormat:(CGLPixelFormatObj)pf forLayerTime:(CFTimeInterval)t displayTime:(const CVTimeStamp *)ts
{
uint32_t plugin_width = 32, plugin_height = 32;
uint32_t width = plugin_width;
uint32_t height = plugin_height;
srand(time(NULL));
for (int i = 0; i < 32*32*4; i ++)
texture_data[i] = rand() % 255;
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_RECTANGLE_EXT, textureName);
glTexSubImage2D (GL_TEXTURE_RECTANGLE_EXT, 0, 0, 0, width, height,GL_BGRA, GL_UNSIGNED_INT_8_8_8_8 ,texture_data);
assert(glGetError() == GL_NO_ERROR); // here i'm getting GL_INVALID_OPERATION
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glBegin(GL_QUADS);
glTexCoord2f(0.0f,0.0f);
glVertex2f(0.0f, 0.0f);
glTexCoord2f(1.0f,0.0f);
glVertex2f(width, 0);
glTexCoord2f(0.0f,1.0f);
glVertex2f(0, height);
glTexCoord2f(1.0f,1.0f);
glVertex2f(width, height);
glEnd();
[super drawInCGLContext:ctx pixelFormat:pf forLayerTime:t displayTime:ts];
}
Did you try to replace the external format GL_UNSIGNED_INT_8_8_8_8 with GL_UNSIGNED_BYTE in both calls (glTexImage2D and glTexSubImage2D)?
That might help.
Related
I am very new to OpenGL
Trying to blend RGB & BGRA raw images.
RGB is backgroung image
RGBA is foregroubng image
With the below source getting the output only ,"osd_raw" image .Blending is not happening.
In the below code loading the 2 raw images .
Creating 2 textures & binding with it.
Used glBlendFunc for blending.
The output is not getting blended.
Please tell me where it's getting wrong.
void display()
{
GLuint texture[2];
int width = 960;
int height = 540;
unsigned char *osd_raw = loadFile("./osd.raw");
unsigned char *video_raw = loadFile("./video.raw");
glClearColor(0.1, 0.1, 0.1, 0.0);
glClear(GL_COLOR_BUFFER_BIT);
glEnable(GL_TEXTURE_2D);
glGenTextures(2, texture);
glEnable( GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, video_raw);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBindTexture(GL_TEXTURE_2D, texture[1]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, osd_raw);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex3f(-1, -1, 0);
glTexCoord2f(0, 1);
glVertex3f(-1, 1, 0);
glTexCoord2f(1, 1);
glVertex3f(1, 1, 0);
glTexCoord2f(1, 0);
glVertex3f(1, -1, 0);
glEnd();
glFlush();
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGBA);
glutInitWindowSize(960, 540);
glutInitWindowPosition(0, 0);
glutCreateWindow("glut test");
glutDisplayFunc(display);
glutMainLoop();
return 0;
}
First of all, note that drawing with glBegin/glEnd sequences is deprecated since more than 10 years.
Read about Fixed Function Pipeline and see Vertex Specification for a state of the art way of rendering.
If you want to blend 2 textures, then you have to bind the first texture and to draw the quad with the proper texture coordinate attributes set.
After that you have to bind the 2nd texture and to draw the quad again, with enabled blending (see Blending):
glDisable( GL_BLEND);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex3f(-1, -1, 0);
glTexCoord2f(0, 1);
glVertex3f(-1, 1, 0);
glTexCoord2f(1, 1);
glVertex3f(1, 1, 0);
glTexCoord2f(1, 0);
glVertex3f(1, -1, 0);
glEnd();
glEnable( GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glBindTexture(GL_TEXTURE_2D, texture[1]);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex3f(-1, -1, 0);
glTexCoord2f(0, 1);
glVertex3f(-1, 1, 0);
glTexCoord2f(1, 1);
glVertex3f(1, 1, 0);
glTexCoord2f(1, 0);
glVertex3f(1, -1, 0);
glEnd();
Further note, that the Depth Test has to be disabled or set to e.g. GL_LEQUAL, when the 2nd quad is drawn. Otherwise the 2nd quad would be discarded by the depth test.
Since the blend function is glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);, of course some alpha channels of the 2nd textue have to be less than 1.0.
As per Rabbid76 ,modified & below is the working source for reference.
void display()
{
GLuint texture[2];
int width = 960;
int height = 540;
unsigned char *osd_raw = loadFile("./osd.raw");
unsigned char *video_raw = loadFile("./video.raw");
glClearColor(0.1, 0.1, 0.1, 0.0);
glClear(GL_COLOR_BUFFER_BIT);
glEnable(GL_TEXTURE_2D);
glGenTextures(2, texture);
glDisable(GL_BLEND);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, video_raw);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex3f(-1, -1, 0);
glTexCoord2f(0, 1);
glVertex3f(-1, 1, 0);
glTexCoord2f(1, 1);
glVertex3f(1, 1, 0);
glTexCoord2f(1, 0);
glVertex3f(1, -1, 0);
glEnd();
glEnable( GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glBindTexture(GL_TEXTURE_2D, texture[1]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, osd_raw);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex3f(-1, -1, 0);
glTexCoord2f(0, 1);
glVertex3f(-1, 1, 0);
glTexCoord2f(1, 1);
glVertex3f(1, 1, 0);
glTexCoord2f(1, 0);
glVertex3f(1, -1, 0);
glEnd();
glFlush();
}
I am trying the texture mapping feature of OpenGL and the texture is displayed on the screen but not on the area that I set.
The area is a quad with 100.0 length and the texture is displayed only on the bottom.
When using GL_RGB in glTexImage2D, only one third of the quad is filled and when I change it to GL_RGBA, it becomes one quarter of the quad.
Main parameters declaration:
BYTE* m_pBMPBuffer;
int m_iWidth;
int m_iHeight;
GLuint m_uiTexture;
Code for setting up the texture mapping:
void CTextureMappingView::InitializeTexture()
{
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glGenTextures(1, &m_uiTexture);
glBindTexture(GL_TEXTURE_2D, m_uiTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, m_iWidth, m_iHeight, 0, GL_BGR, GL_UNSIGNED_BYTE, m_pBMPBuffer);
}
Buffer Initialization:
m_iWidth = 64;
m_iHeight = 64;
m_pBMPBuffer = new BYTE[m_iWidth * m_iHeight * 3];
for (int i = 0 ; i < m_iWidth * m_iHeight ; i += 3)
{
m_pBMPBuffer[i] = 255;
m_pBMPBuffer[i + 1] = 0;
m_pBMPBuffer[i + 2] = 0;
}
Rendering:
void CTextureMappingView::RenderScene()
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glRotatef(XAngle, 1.0f, 0.0f, 0.0f);
glRotatef(YAngle, 0.0f, 1.0f, 0.0f);
glPushMatrix();
glEnable(GL_TEXTURE_2D);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glBindTexture(GL_TEXTURE_2D, m_uiTexture);
glBegin(GL_POLYGON);
glTexCoord2d(0.0, 0.0);
glVertex3d(0.0, 0.0, 0.0);
glTexCoord2d(0.0, 1.0);
glVertex3d(0.0, 100.0, 0.0);
glTexCoord2d(1.0, 1.0);
glVertex3d(100.0, 100.0, 0.0);
glTexCoord2d(1.0, 0.0);
glVertex3d(100.0, 0.0, 0.0);
glEnd();
glDisable(GL_TEXTURE_2D);
glPopMatrix();
}
Current result:
You only initialize a third of your texture:
for (int i = 0 ; i < m_iWidth * m_iHeight ; i += 3)
You should go up to m_iWidth * m_iHeight * 3 since that's what you allocated.
I want to apply gaussian blur in a 256x256 texture but Im having problems passing the first pass to a framebuffer and reusing it actualy result in part of image, that appear to be the texture transformed.
Tanks the attention
vertex shader:
void main()
{
gl_Position = ftransform();
gl_TexCoord[0] = gl_MultiTexCoord0;
}
fragment shader:
I removed all the part of blurring only to tests.
uniform sampler2D texture_0;
uniform float switcher;
vec4 cor;
void main()
{
cor = vec4(0.0,0.0,0.0,0.0);
vec2 position = gl_TexCoord[0].xy;
cor = texture2D(texture_0,position);
gl_FragColor = cor;
}
initializations:
glGenTextures( 1, &tex1 );
glBindTexture( GL_TEXTURE_2D, tex1 );
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img1->getWidth(),img1->getHeight(), 0,GL_RGB, GL_UNSIGNED_BYTE, data1);
glBindTexture(GL_TEXTURE_2D, 0);
glGenTextures( 1, &tex2 );
glBindTexture( GL_TEXTURE_2D, tex2 );
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img1->getWidth(),img1->getHeight(), 0,GL_RGB, GL_UNSIGNED_BYTE, 0);
glBindTexture(GL_TEXTURE_2D, 0);
glEnable(GL_TEXTURE_2D);
glActiveTexture(GL_TEXTURE0);
glBindTexture( GL_TEXTURE_2D, tex1 );
glActiveTexture(GL_TEXTURE1);
glBindTexture( GL_TEXTURE_2D, tex2 );
glGenFramebuffers(1,&framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER,framebuffer);
glFramebufferTexture2D(GL_FRAMEBUFFER,GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex2,0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
render:
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glUniform1i(loc_u_texture_0, 0);
glUniform1f(loc_switcher_1, 0);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
glNormal3f(0, 1, 0);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex3f(-2, -2, -10);
glTexCoord2f(1, 0);
glVertex3f(2, -2, -10);
glTexCoord2f(1, 1);
glVertex3f(2, 2, -10);
glTexCoord2f(0, 1);
glVertex3f(-2, 2, -10);
glEnd();
glBindFramebuffer(GL_FRAMEBUFFER, 0);
usleep(50);
glUniform1i(loc_u_texture_0, 1);
glUniform1f(loc_switcher_1, 1);
glNormal3f(0, 1, 0);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex3f(-2, -2, -10);
glTexCoord2f(1, 0);
glVertex3f(2, -2, -10);
glTexCoord2f(1, 1);
glVertex3f(2, 2, -10);
glTexCoord2f(0, 1);
glVertex3f(-2, 2, -10);
glEnd();
glutSwapBuffers();
Use the following lines to draw a quad:
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(-1.0f, -1.0f, 0.0f);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(1.0f, -1.0f, 0.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(1.0f, 1.0f, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, 0.0f);
glEnd();
When you reset both the projection and the modelview matrices, your primitives are not transformed and you can directly draw objects in clipping space (which is a cube with corners (-1,-1,-1) and (1,1,1)).
Also, don't use the following:
glActiveTexture(GL_TEXTURE1);
glBindTexture( GL_TEXTURE_2D, tex2 );
if you are not going to use more than one input sampler per shader at the same time, you need only the first texture channel GL_TEXTURE0, which is set by default.
I must be missing something obvious in using FBO :
I call TMyForm::Init() once at the start of my application :
class TMyForm
{ ...
private:
Gluint mTextureId, mFboId;
int mWidth, mHeight;
}
void TMyForm::Init()
{
mWidth = 1920;
mHeight = 1080;
...
// create a texture object
glEnable(GL_TEXTURE_2D);
glClearColor ( 0.0, 0.0, 0.0, 1.0 );
glGenTextures(1, &mTextureId);
glBindTexture(GL_TEXTURE_2D, mTextureId);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE); // automatic mipmap
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1920, 1080, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
glBindTexture(GL_TEXTURE_2D, 0);
// create a framebuffer object
glGenFramebuffersEXT(1, &mFboId);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, mFboId);
// attach the texture to FBO color attachment point
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, mTextureId, 0);
// switch back to window-system-provided framebuffer
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
}
And in the Draw() function I send the buffer to a card (the rendered scene is ok) and to a preview window (all black or all white depending if I switch back to default window context or the fbo context) :
void TMyForm::Draw()
{
// set rendering destination to FBO
glEnable(GL_TEXTURE_2D);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, mFboId);
//---
glViewport(-1920, -1080, 1920 * 2, 1080 * 2);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(double(-iWidth)*viewport_ratio, double(iWidth)*viewport_ratio, double(-iHeight), double(iHeight), 1000.0, 100000.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
Render();
glFlush();
//--- 1 : send to card
delete[] mBufferPlayout;
mBufferPlayout = NULL;
try
{
mBufferPlayout = new GLubyte [mWidth * mHeight * 4];
glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
glReadPixels(0,0, mWidth, mHeight, GL_BGRA_EXT, GL_UNSIGNED_BYTE, mBufferPlayout);
DisplayFrame(mBufferPlayout);
}
catch (TSCDbException &e) { ShowMessage(GetLastError()); }
//--- 2 : Texturing to the preview window :
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
glClear(GL_COLOR_BUFFER_BIT);
glBindTexture(GL_TEXTURE_2D, mTextureId);
//glGenerateMipmapEXT(GL_TEXTURE_2D);
int iWidthPreview = mWidth / 2; // ie 960
int iHeightPreview = mHeight / 2; // ie 540
glViewport(-iWidthPreview, -iHeightPreview, iWidthPreview * 2, iHeightPreview * 2);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(double(-iWidthPreview), double(iWidthPreview), double(-iHeightPreview), double(iHeightPreview), 1000.0, 100000.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, 0.0, -50000.0);
mxIncrust0 = 0.0; myIncrust0 = 0.0;
mxIncrust1 = iWidthPreview; myIncrust1 = iHeightPreview;
glBegin(GL_QUADS);
glColor4ub(255,255,255,255);
glTexCoord2d(0.0, 0.0); glVertex2d(mxIncrust0, myIncrust0);
glTexCoord2d(0.0, 1.0); glVertex2d(mxIncrust0, myIncrust1);
glTexCoord2d(1.0,1.0); glVertex2d(mxIncrust1, myIncrust1);
glTexCoord2d(1.0,0.0); glVertex2d(mxIncrust1, myIncrust0);
glEnd();
glDisable(GL_TEXTURE_2D);
glFlush();
//---
SwapBuffers(ghDC);
}
So my problem is the "part 2" which does not do what I wish : texturing the fbo content to the current window.
I tried changing the "glTexCoord2d" with no success.
I'm trying to perform hidden line removal using polygon offset fill. The code works perfectly if I render directly to the window buffer but fails to draw the lines when passed through a FBO as shown below
The code I use to draw the objects
void drawCubes (GLboolean removeHiddenLines)
{
glLineWidth(2.0);
glPushMatrix();
camera.ApplyCameraTransform();
for(int i = 0; i < 50; i ++){
glPushMatrix();
cube[i].updatePerspective();
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
glColor3f(1.0,1.0,1.0);
cube[i].draw();
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
if(removeHiddenLines){
glEnable(GL_POLYGON_OFFSET_FILL);
glPolygonOffset(1.0, 1.0);
glColor3f(1.0, 0.0, 0.0); //fill polygons for hidden line removal
cube[i].draw();
glDisable(GL_POLYGON_OFFSET_FILL);
}
glPopMatrix();
}
glPopMatrix();
}
For this example, the first pass involves rendering to both the window buffer and a FBO.
void firstPass()
{
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glViewport(0, 0, fboWidth, fboHeight);
glEnable(GL_DEPTH_TEST);
glDisable(GL_TEXTURE_2D);
drawParticleView(GL_TRUE);
glDisable(GL_DEPTH_TEST);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID[1]);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glViewport(0, 0, fboWidth, fboHeight);
glEnable(GL_DEPTH_TEST);
glDisable(GL_TEXTURE_2D);
drawParticleView(GL_TRUE);
glDisable(GL_DEPTH_TEST);
}
Second pass renders FBO back to window buffer.
void secondPass()
{
glEnable(GL_TEXTURE_2D);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
glBindTexture(GL_TEXTURE_2D, renderTextureID[0]);
glViewport(fboWidth, 0, fboWidth, fboHeight);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glBegin(GL_QUADS);
glTexCoord2i(0, 0);
glVertex2f(-1.0f, -1.0f);
glTexCoord2i(1, 0);
glVertex2f(1.0f, -1.0f);
glTexCoord2i(1, 1);
glVertex2f(1.0f, 1.0f);
glTexCoord2i(0, 1);
glVertex2f(-1.0f, 1.0f);
glEnd();
glDisable(GL_TEXTURE_2D);
}
Setup FBO's
void setupRC()
{
setupTextures();
glGenFramebuffersEXT(2, framebufferID);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID[0]);
glGenRenderbuffersEXT(1, &renderbufferID);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, renderbufferID);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT32, fboWidth, fboHeight);
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, renderbufferID);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, renderTextureID[0], 0);
GLenum fboStatus = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
if(fboStatus != GL_FRAMEBUFFER_COMPLETE_EXT){
fprintf(stderr, "FBO #1 Error!");
}
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID[1]);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, renderTextureID[1], 0);
fboStatus = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
if(fboStatus != GL_FRAMEBUFFER_COMPLETE_EXT){
fprintf(stderr, "FBO #2 Error!");
}
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
}
Setup textures
void setupTextures(void)
{
glGenTextures(2, renderTextureID);
for (GLint i = 0; i < 2; i++){
glBindTexture(GL_TEXTURE_2D, renderTextureID[i]);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// this may change with window size changes
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, fboWidth, fboHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
}
glBindTexture(GL_TEXTURE_2D, 0);
}
I don't understand why the two views wouldn't be the same? Am I missing something (obviously I am)?
Thanks
The problem is that I was rendering to a FBO without a depth attachment. Setting up the second FBO the same as the first gave the correct results.
Your code seems ok to me. The weird stuff is that you still have the red cube drawn, but not the lines... What is your OpenGL implementation, driver version?
Can you test without enabling GL_POLYGON_OFFSET_FILL and/or glLineWidth to see if you see the lines (albeit hidden parts visible)?