Shader Linking

In order to pass data between the vertex and fragment shader, a sort of link-program seems to be copying from the output of the vertex shader into the TRAM (the RAM used as input to rasterization and shading).

This program is located at offset 0x300 and upwards, and seems to have 64-bit words. Here's an example:

0x00000008
0x0000fecd

This copies four floats from each vertex.

The first word seems to contain the location to copy from in the vertex shader, the latter word contains the location in the fragment shader.

The latter word contains the following for single varyings (for a simple dot product-shader):

datatype	value
lowp float	0x00b7
mediump float	0x000f
lowp vec2	0x00b7
mediump vec2	0x00fe
lowp vec3	0xb7a6
mediump vec3	0x0dfe
lowp vec4	0xa6b7
mediump vec4	0xcdfe

In addition to this, something is going on at offset 0xe20 and upwards:

0x58000000