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POProblems with glDrawTex_OES
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copied!<p>I'm not sure I'm using glDrawTex_OES correctly. In fact, I'm sure I'm not because I'm getting a black rectangle on the screen rather than the intended texture.</p> <p>To get the silly points out of the way: Yes, the GL Extension string contains the OES_draw_texture token. Yes, the texture is loaded into memory/etc. correctly: it displays just fine if I map it to a polygon.</p> <p>From reading the various bits of <a href="http://www.khronos.org/registry/gles/extensions/OES/OES_draw_texture.txt" rel="nofollow noreferrer">documentation I can find</a> for it, it looks like I need to "configur[e] the texture crop rectangle ... via TexParameteriv() with pname equal to TEXTURE_CROP_RECT_OES". According to <a href="http://www.khronos.org/message_boards/viewtopic.php?p=2450&sid=5242c63d39af53a2c39769bc0b04ffbf" rel="nofollow noreferrer">this post</a> in the khronos forums (best documentation google can find for me), the values for that are "Ucr, Vcr, Wcr, Hcr. That is, left/bottom/width/height"</p> <p>Here's the render code:</p> <pre><code>void SetUpCamera( int windowWidth, int windowHeight, bool ortho ) // only called once { glViewport( 0, 0, windowWidth, windowHeight ); glMatrixMode( GL_PROJECTION ); glLoadIdentity(); if( ortho ) { float aspect = (float)windowWidth / (float)windowHeight; float halfHeight = 32; glOrthof( -halfHeight*aspect, halfHeight*aspect, -halfHeight, halfHeight, 1.0f, 100.0f ); } else { mygluPerspective( 45.0f, (float)windowWidth / (float)windowHeight, 1.0f, 100.0f ); // I don't _actually_ have glu, but that's irrelevant--this does what you'd expect. } } void DrawTexture( int windowWidth, int windowHeight, int texID ) { // Clear back/depth buffer glClearColor( 1, 1, 1, 1 ); glClearDepth( 1.0f ); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); // Next 2 lines probably not necessary, but, you know, sanity check: glMatrixMode( GL_MODELVIEW ); glLoadIdentity(); // set up texture glBindTexture( GL_TEXTURE_2D, texID ); // texID is the glGenTexture result for a 64x64 2D RGB_8 texture - nothing crazy. GLint coords [] = {0, 0, 64, 64}; glTexParameteriv( GL_TEXTURE_2D, GL_TEXTURE_CROP_RECT_OES, coords ); // blit? =( glDrawTexiOES( windowWidth / 2 - 32, windowHeight - 70, 10, 64, 64 ); } </code></pre> <p>Am I missing something obvious? Doing anything just plain dumb?</p>

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