View Full Version : dynamic indexing in arrays ?¿ is it possible?

03-21-2006, 07:40 AM
we are developing some GPU algorithm which involves indexing an array with an index calculated from an uniform and gl_color/vertex information.

Have anybody tried to do something similar ?

Thank you in advance.

03-21-2006, 07:49 AM
i forgot to add some code snippet:

uniform vec2 weight;

int index = gl_Vertex.y * weight[0] + gl_Color.y * weight[1];

float res[4];


res[index] = 1; // "lvalue too complex"
float a = res[index]; //"exception during compilation"

the error messages come after linking, with no problem in compilation time.

03-21-2006, 07:54 AM

float v[4];

v[int(gl_Vertex.x)] = 1.; // "lvalue too complex"

gl_Position.x = v[int(gl_Vertex.x)]; //"exception during compilation"

so strange message after compiling without error..

*Note1: we are using ShaderDesigner 1.5.9 to test -> Generic Compilation does not report any problem.
*Note2: 3dlabs GLSLValidate returns CORRECT!

03-22-2006, 02:27 AM
As far as I am aware current hardware cannot do arbitary indexing, you can only index into uniform arrays.

If your arrays are small you can probably just use a "switch statement" to select.