[GEM-dev] frambuffer and Vertex Texture Fetching

[cyrille henry]

hello,
i'm currently investigating the use of framebuffer to create a texture in order to use it as a vertex displacement.
this has already been discuss in this list, but new stuff in framebuffer makes me try again.

i'm specially motived because it's the last things that prevent me trying physical modeling in glsl.



having a look at framebuffer, i noticed strange things : 

-changing type or format does not init the framebuffer, you have to change dim, or rectangle (mode) in order to init it.
(i don't know why)

-in void gemframebuffer :: typeMess(char* type), should :

	else if (!strcmp(type, "FLOAT")){
	  post("type is GL_FLOAT, %d",m_type);
	  m_type = GL_FLOAT;
	  return;

be replaced by : 
	else if (!strcmp(type, "FLOAT")){
	  m_type = GL_FLOAT;
	  post("type is GL_FLOAT, %d",m_type);
	  return;
??? 

(it's also the same in formatMess)

anyway. here are the good news : 

i add (and commit) a RGB32 format corresponding to 
        m_internalformat = GL_RGB_FLOAT32_ATI;
#ifdef __APPLE__
        m_format = GL_BGR;
#else 
        m_format = GL_RGB;
#endif
(i  don't know if apple definition is ok).

but the internal format GL_RGB_FLOAT32_ATI was mandatory in order to have an efficient implementation of vertex texture fetching.

so here is an example. it still need to be cleaned, but i'd like to know if it work on other computer.
(here, it's about 50 time faster than previous example i send to this list)

please update/compile and test!

cyrille
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