Imagination PowerVR SDK Blog

glBlendFunc() does not work well in ES2 SDK


#1
I use ES2 SDK on WINXP.

 

When I using glBlendFunc() function with GL_ONE_MINUS_DST_ALPHA or GL_DST_ALPHA

 

GL_ONE_MINUS_DST_ALPHA works like GL_ZERO and GL_DST_ALPHA works like GL_ONE

 

DST alpha value does not applied

 

glBlendFunc(GL_DST_ALPHA, GL_ZERO);
glEnable(GL_BLEND);
glClearColor(1.0f, 1.0f, 1.0f, 0.1f);
glClear(GL_COLOR_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES, 0, 3);

 

even alpha value of clear color is 0.1f result sfactor is 1.0f
k2cdda2008-04-14 10:44:08

#2

Could you please check that the surface you are rendering to has an alpha channel, i.e. does the EGL config you used for surface creation have EGL_ALPHA_SIZE > 0?Xmas2008-04-14 11:57:09