OpenGL texturing Triangles

Question

I have a varray full of triangles that make a large square. I'm trying to texture this large square and all i'm getting (it seems) is a one pixel column that is then stretched across the primitive.

I'm texturing each right angled triangle with UV coords (0,1), (0,0), (1,0) and (0,1), (1,1), (1,0) depending on which way up the triangle is.

rendering code.

    glBindTexture(GL_TEXTURE_2D, m_texture.id());

    //glEnableClientState(GL_INDEX_ARRAY);
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_NORMAL_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    //glIndexPointer(GL_INT, 0, &m_indices[0]);
    glVertexPointer(3, GL_FLOAT, sizeof(VertexData), &m_vertexData[0].x);
    glNormalPointer(GL_FLOAT, sizeof(VertexData), &m_vertexData[0].nx);
    glTexCoordPointer(2, GL_FLOAT, sizeof(UVData), &m_uvData[0].u);

    glDrawElements(GL_TRIANGLES, m_indices.size(), GL_UNSIGNED_INT, &m_indices[0]);
    glBindTexture(GL_TEXTURE_2D, 0);

texture is wrap mode is GL_CLAMP_TO_EDGE

Screenshot

EDIT

outputting the first two triangles i get values ...

Triangle 1:

Indices(0,1,31)

Vertex0 (-15, 0, -15), Vertex1 (-15,0,-14), Vertex31 (-14, 0, -14)

UV (0,1), (0,0), (1,0)

Triangle 2:

Indices(0, 30, 31)

Vertex0(-15, 0, -15), Vertex30(-14, 0, -15) Vertex31 (-14, 0, -14)

UV (0, 1), (1, 1), (1, 0)

For posterity the full code is here

The two triangles make up a square with the diagonal cut from top left to bottom right.

Answer 1

不要使用glIndexPointer，不是你想的那样，用于颜色索引模式，做索引网格只需使用glDrawElements。

Answer 2

Looks like you're associating the UV data with the indices, not with the vertices. UV data is part of the vertex data, so you should probably pack it in the VertexData object, rather than keeping it separate. You can keep it separate, but you need one per vertex, not one per index.