Scenegraph rewrite

[NaN]

I've been thinking about multi texturing before the shaders came up.

I think we could emulate texture vertex color blending:

Code:

gl_FragColor.rgb = mix(gl_Color.rgb, tu0_2D_val.rgb, tu0_2D_val.a);

with:

Code:

glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_INTERPOLATE);
glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB, GL_PRIMARY_COLOR_ARB);
glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB, GL_TEXTURE);
glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE2_RGB, GL_TEXTURE);
glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_RGB, GL_SRC_COLOR);
glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_RGB, GL_SRC_ALPHA);

But I don't know how to combine the alphas:

Code:

gl_FragColor.a = tu0_2D_val.a + 2 * gl_Color.a - 1;

Does it make sense to use texture combiners? I think they have been deprecated in OpenGL 3.0. I just want to avoid doing it in software.