I'm trying to draw some OpenGL graphics over the video from camera. I've modified Apple's GLCameraRipple sample with code that draws a couple of textured triangles. This code works well in my another OpenGL project (but without GLKit). Unfortunately, it only works here that way: when my app starts I see screen filled with ClearColor with my textured triangles on it (but no video), and in a moment the screen turns to black and I don't see anything. Could you explain me what's the problem is?
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
{
glClearColor(0.5, 0.0, 0.0, 0.3);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(_program);
glUniform1i(uniforms[UNIFORM_Y], 0);
glUniform1i(uniforms[UNIFORM_UV], 1);
if (_ripple)
{
glDrawElements(GL_TRIANGLE_STRIP, [_ripple getIndexCount], GL_UNSIGNED_SHORT, 0);
}
[self drawAnimations];
}
- (void) drawAnimations{
// Use shader program.
glUseProgram(_texturingProgram);
GLfloat modelviewProj[16];
[self MakeMatrix:modelviewProj
OriginX:100.0
OriginY:100.0
Width:200.0
Height:200.0
Rotation:0.0];
// update uniform values
glUniformMatrix4fv(texturing_uniforms[TEXTURING_UNIFORM_MODEL_VIEW_PROJECTION_MATRIX], 1, GL_FALSE, modelviewProj);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, _animationTexture);
glUniform1i(texturing_uniforms[TEXTURING_UNIFORM_TEXTURE], 0);
glVertexAttribPointer(TEXTURING_ATTRIB_VERTEX,3, GL_FLOAT, GL_FALSE, sizeof(vertexDataTextured), &plain[0].vertex);
glEnableVertexAttribArray(TEXTURING_ATTRIB_VERTEX);
glVertexAttribPointer(TEXTURING_ATTRIB_TEX_COORDS, 2, GL_FLOAT, GL_FALSE, sizeof(vertexDataTextured), &plain[0].texCoord);
glEnableVertexAttribArray(TEXTURING_ATTRIB_TEX_COORDS);
glDrawArrays(GL_TRIANGLES, 0, 6);
if (![self validateProgram:_texturingProgram]) {
NSLog(@"Failed to validate program: (%d)", _texturingProgram);
}
}
