基于模型空间顶点Z坐标的颜色简单顶点着色器

Question

我有一个简单的函数map_color，用于计算我大学的侵蚀模拟器的顶点颜色。我想将其转换为顶点着色器。对我的第一个着色器来说似乎很简单，但我不知道从哪里开始。我看过几个代码样本似乎很有希望，但过于复杂，我很难遵循。

我应该提一下，我正在使用java / jogl，但我可以查看加载着色器并自行打开它的详细信息。主要是寻找实际着色器代码的帮助。

private void map_color(float height, float color[])
    {

        float t = (height - COLOR_MIN_HEIGHT) / (COLOR_MAX_HEIGHT - COLOR_MIN_HEIGHT);

        // Clamp to range, just in case
        if(t < 0.0) t = 0.0f;
        if(t > 1.0) t = 1.0f;

        // Brown yellow map
        if (t < 0.5)
        {
            color[0] = 0.488f + t * 0.836f;
            color[1] = 0.164f + t * 0.953f;
            color[2] = 0.094f + t * 0.172f;
        }
        else
        {
            color[0] = 0.906f + (t - 0.5f) * 0.180f;
            color[1] = 0.640f + (t - 0.5f) * 0.680f;
            color[2] = 0.180f + (t - 0.5f) * 0.773f;
        }

    }
    private void drawTerrain()
        {
            // Need a separate vertex normal for each quad -- this implementation is inefficient
            // Should be computed once and stored when grid is loaded

        float [] v1 = new float[3];
        float [] v2 = new float[3];
        float [] norm = new float[3];
        float [] color = new float[3];

        v1[0] = gridHorizontalScaleFactor / 5.0f;  // Scale factor is a hack
        v1[1] = 0.0f;

        v2[0] = 0.0f;
        v2[1] = gridHorizontalScaleFactor / 5.0f;  // Ditto on hack

        // Get ready for varying material properties
        gl.glEnable(GLLightingFunc.GL_COLOR_MATERIAL);
        gl.glColorMaterial(GL.GL_FRONT_AND_BACK,
                GLLightingFunc.GL_AMBIENT_AND_DIFFUSE);

        for(int x = 2; x < latticeSizeX-1; x++)
        {
            for(int y = 2; y < latticeSizeY-1; y++)
            {
                gl.glBegin(GL.GL_TRIANGLES);
                v1[2] = unsafeTopo.getFloatAt((x+1) * 263 + y) - unsafeTopo.getFloatAt( (x-1) * 263 + y);
                v2[2] = unsafeTopo.getFloatAt(x * 263 + (y + 1)) - unsafeTopo.getFloatAt( x * 263 + (y - 1));

                cross(norm, v2, v1);

                gl.glNormal3fv(norm, 0);

                map_color(unsafeTopo.getFloatAt(x * 263 + y), color);
                gl.glColor3f(color[0], color[1], color[2]);
                gl.glVertex3f(x,   y,   unsafeTopo.getFloatAt(x * 263 + y));

                map_color(unsafeTopo.getFloatAt((x+1) * 263 + y), color);
                gl.glColor3f(color[0], color[1], color[2]);
                gl.glVertex3f(x+1, y,   unsafeTopo.getFloatAt((x+1) * 263 + y));

                map_color(unsafeTopo.getFloatAt(x * 263 + (y + 1)), color);
                gl.glColor3f(color[0], color[1], color[2]);
                gl.glVertex3f(x,   y+1, unsafeTopo.getFloatAt(x * 263 + (y + 1)));

                v1[2] = unsafeTopo.getFloatAt((x+2) * 263 + y+1) - unsafeTopo.getFloatAt(x * 263 + (y + 1));
                v2[2] = unsafeTopo.getFloatAt((x+1) * 263 + y+2) - unsafeTopo.getFloatAt((x+1) * 263 + y);

                cross(norm, v2, v1);

                map_color(unsafeTopo.getFloatAt((x+1) * 263 + y+1), color);
                gl.glColor3f(color[0], color[1], color[2]);
                gl.glVertex3f(x+1, y+1, unsafeTopo.getFloatAt((x+1) * 263 + y+1));

                map_color(unsafeTopo.getFloatAt(x * 263 + (y + 1)), color);
                gl.glColor3f(color[0], color[1], color[2]);
                gl.glVertex3f(x,   y+1, unsafeTopo.getFloatAt(x * 263 + (y + 1)));

                map_color(unsafeTopo.getFloatAt((x+1) * 263 + y), color);
                gl.glColor3f(color[0], color[1], color[2]);
                gl.glVertex3f(x+1, y,   unsafeTopo.getFloatAt((x+1) * 263 + y));

                gl.glEnd();
            }
        }
        gl.glDisable(GLLightingFunc.GL_COLOR_MATERIAL);
    }