Texture blending without RGBA

OpenGL OpenGL: Basic Coding
1

I’m having a bit of greif with the snippet below.

What i’m trying to do is draw some grass, then on-top draw some snow.

The grass and snow both draw fine when the other isn’t being drawn… i can’t seem to get them to be drawn together.

I’m sure this is a really simple mistake - can anyone spot it?

    // Draw Grass

    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, 1);
    glBegin(GL_QUADS);
    glColor4f(1.0, 1.0, 1.0, 1.0);

    // Draws the grass tile

    glEnd();

    // Draw Snow
    glEnable(GL_BLEND);
    glBindTexture(GL_TEXTURE_2D, 2);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glBegin(GL_QUADS);
    glColor4f(1.0, 1.0, 1.0, 0.5);

    // Draws the snow tile

    glEnd();
    glDisable(GL_BLEND);
    glDisable(GL_TEXTURE_2D);

[This message has been edited by nickcartwright (edited 10-13-2003).]

[This message has been edited by nickcartwright (edited 10-13-2003).]

2

Looks like you need glColorMaterial turned on so that you can glColor4f() and have textures at the same time. I may be mislead here though. I suppose you can also try affecting the color matrix as well. You shouldn’t need to have an alpha channel in your texture though.

3

You could try setting the alpha for the first texture to 0.5, or maybe setting the alpha in glClearColor to 0.5 or 0 if it’s at 1.

//texture 1
glColor4f(1,1,1,0.5);
glClearColor(1,1,1,0);

This might work.