crash in glVertexAttribIPointer (integer version!)

OpenGL OpenGL: Advanced Coding
1

[solved]

hi

i am using generic vertex attributes to transfer all my vertex data to the vertex shader. one of the attributes is of type integer which i need as integer in the shader, so i use glVertexAttribIPointer. unfortunately, this call crashes. it works fine when i use a float attribute and glVertexAttribPointer.

here’s the relevant code:


struct MyVertex
{
  float x, y, z;    // 12 bytes
  float nx, ny, nz; // 12 bytes
  float tx, ty, tz; // 12 bytes
  float u, v;       // 8 bytes
  float dx, dy;     // 8 bytes
  int r;	    // 4 bytes
  float pad[2];     // to make it 64bytes
};


void render() {
  glBindBuffer(GL_ARRAY_BUFFER, mVBO);
 
  glEnableVertexAttribArray(mAttribLocs[0]);
  glEnableVertexAttribArray(mAttribLocs[1]);
  glEnableVertexAttribArray(mAttribLocs[2]);
  glEnableVertexAttribArray(mAttribLocs[3]);   
  glEnableVertexAttribArray(mAttribLocs[4]);
  glEnableVertexAttribArray(mAttribLocs[5]);

  glVertexAttribPointer(mAttribLocs[0], 3, GL_FLOAT, GL_FALSE, sizeof(MyVertex), (GLvoid*)offsetof(MyVertex, x));
  glVertexAttribPointer(mAttribLocs[1], 3, GL_FLOAT, GL_FALSE, sizeof(MyVertex), (GLvoid*)offsetof(MyVertex, nx));
  glVertexAttribPointer(mAttribLocs[2], 3, GL_FLOAT, GL_FALSE, sizeof(MyVertex), (GLvoid*)offsetof(MyVertex, tx));
  glVertexAttribPointer(mAttribLocs[3], 2, GL_FLOAT, GL_FALSE, sizeof(MyVertex), (GLvoid*)offsetof(MyVertex, u));
  glVertexAttribPointer(mAttribLocs[4], 2, GL_FLOAT, GL_FALSE, sizeof(MyVertex), (GLvoid*)offsetof(MyVertex, dx));
  // next line CRASHES
  glVertexAttribIPointer(mAttribLocs[5], 1, GL_INT, sizeof(MyVertex), (GLvoid*)offsetof(MyVertex, r)); 
  // works fine: glVertexAttribPointer(mAttribLocs[5], 1, GL_FLOAT, GL_FALSE, sizeof(MyVertex), (GLvoid*)offsetof(MyVertex, r)); 

  glCullFace(GL_BACK);
  glDisable(GL_STENCIL_TEST);
  glDisable(GL_ALPHA_TEST);
  glDisable(GL_BLEND);
  glEnable(GL_DEPTH_TEST);
  glDisable(GL_LIGHTING);
  glDepthFunc(GL_LESS); 
  glDisable(GL_TEXTURE_2D);

  glMultiDrawArrays(GL_POLYGON, (GLint*)&mStartIndices[0], (GLsizei*)&mFaceCounts[0], (GLsizei)mStartIndices.size());

  for (size_t i = 0; i < 6; ++i)
    glDisableVertexAttribArray(mAttribLocs[i]);

  glBindBuffer(GL_ARRAY_BUFFER, 0);
}

edit: here’s part of the vertex shader


#version 130
#extension GL_EXT_gpu_shader4 : enable

in vec3 InVertex;
in vec3 InNormal;
in vec3 InTangent;
in vec2 InTexCoord0;
in vec2 InFacDim;
in int InRule; // <-- attribute in question

flat out int startRule;
...

void main(void) 
{
   ...
   startRule = InRule; // transmit non-interpolated to fragment
   ...

i use a macbookpro with nvidia 9600M and drivers 197.13 on vista64

thanks in advance,
simon

2

Does the glVertexAttribIPointer function point to NULL?

Regards
elFarto

3

hi

thanks for bringing me on the right track… i was looking at the wrong places.

indeed the function pointer was zero, using the EXT version works.

cheers,
simon