Code Snippets

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This page of the wiki is a sharing zone for rough Horde example code.

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More procedurally generated content code

The following is similar but different to the Procedurally generated geometry tutorial

Building a 2D grid of points

void ScreenGridMesh( char*& data, int& fileSize, int& batchStart, int& batchCount, int& vertRStart, int& vertREnd ) { extern int appWidth; extern int appHeight; //This example splits the screen up into groups of 16 pixels, and create a quad for each group. int quadSize = 16; int quadSizeHalf = quadSize/2; int quadsH = (appWidth +quadSize-1) / quadSize;//divide by 16, rounding up int quadsV = (appHeight+quadSize-1) / quadSize; int quads = quadsH*quadsV; int version = 5; int numJoints = 0;//I don't have code below for writing joints... int numMorphTargets = 0;//...or morph targets //The lines that begin with //! or /*! could be used if you want a more complete vertex format (i.e. normal/binormal/tangent/joints/etc) //! int numVertexStreams = 8; int numVertexStreams = 2;//I'm just using position + tex-coord int numVertices = quads * 4;// I'm making 4 verts per quad int numTriangleIndices = quads * 6;//Each quad is 2 triangles. Each triangle is made up of 3 verts, so I need 6 indices to describe each quad. int vertPositionID = 0; int vertNormalID = 1; int vertTangentID = 2; int vertBiTangentID = 3; int vertJointIndexID = 4; int vertJointWeightID = 5; int vertTexCoordID = 6; int vertTexCoord2ID = 7; int positionElementSize = sizeof(float)*3; int normalElementSize = sizeof(short)*3; int tangentElementSize = sizeof(short)*3; int biTangentElementSize= sizeof(short)*3; int jointIndexElementSize = sizeof(char)*4; int jointWeightElementSize = sizeof(char)*4; int texCoordElementSize = sizeof(float)*2; int texCoord2ElementSize = sizeof(float)*2; batchStart = 0; batchCount = numTriangleIndices; vertRStart = 0; vertREnd = numVertices-1; //! int vertDataSize = positionElementSize+normalElementSize+ tangentElementSize+biTangentElementSize+ jointIndexElementSize+jointWeightElementSize+ texCoordElementSize+texCoord2ElementSize; int vertDataSize = positionElementSize+texCoordElementSize; int quadDataSize = vertDataSize*4 + sizeof(int)*6; //! fileSize = sizeof(char)*4 + sizeof(int)*22 + quadDataSize*quads; fileSize = sizeof(char)*4 + sizeof(int)*10 + quadDataSize*quads; data = new char[fileSize]; int written = 0; #define ASSERT( c ) \ if( !(c) ) { printf( "ASSERTION FAILED: %s\n", #c ); breakPlz(); } #define WRITE_DATA( d, size ) \ memcpy( &data[written], d, size ); written += size; ASSERT( written <= fileSize ); //First write the header WRITE_DATA( "H3DG", sizeof(char)*4 ); WRITE_DATA( &version, sizeof(int) ); //Joint data would go here, if I had any WRITE_DATA( &numJoints, sizeof(int) ); //Then write the vertex-stream header WRITE_DATA( &numVertexStreams, sizeof(int) ); WRITE_DATA( &numVertices, sizeof(int) ); //I'm making quads in this example, so all my loops are going to create 4 pieces of each data. //To begin with I write the positions: WRITE_DATA( &vertPositionID, sizeof(int) ); WRITE_DATA( &positionElementSize, sizeof(int) ); for( int y=0; y<quadsV; ++y ) { for( int x=0; x<quadsH; ++x ) { float positionA[3] = { ((x+0.0f)/(float)quadsH)*2.0f-1.0f, ((y+0.0f)/(float)quadsV)*2.0f-1.0f, 0.0f }; float positionB[3] = { ((x+1.0f)/(float)quadsH)*2.0f-1.0f, ((y+0.0f)/(float)quadsV)*2.0f-1.0f, 0.0f }; float positionC[3] = { ((x+1.0f)/(float)quadsH)*2.0f-1.0f, ((y+1.0f)/(float)quadsV)*2.0f-1.0f, 0.0f }; float positionD[3] = { ((x+0.0f)/(float)quadsH)*2.0f-1.0f, ((y+1.0f)/(float)quadsV)*2.0f-1.0f, 0.0f }; WRITE_DATA( positionA, sizeof(float)*3 ); WRITE_DATA( positionB, sizeof(float)*3 ); WRITE_DATA( positionC, sizeof(float)*3 ); WRITE_DATA( positionD, sizeof(float)*3 ); } } /*! //Normals/binormals/tangents should be floats in the 0-1 range, and then multiplied by 32767 and cast to 'short'. This is a form of compression. WRITE_DATA( &vertNormalID, sizeof(int) ); WRITE_DATA( &normalElementSize, sizeof(int) ); for( int i=0; i!=quads; ++i ) { short n[] = { 0, 0, 32767 }; WRITE_DATA( n, sizeof(short)*3 ); WRITE_DATA( n, sizeof(short)*3 ); WRITE_DATA( n, sizeof(short)*3 ); WRITE_DATA( n, sizeof(short)*3 ); } WRITE_DATA( &vertTangentID, sizeof(int) ); WRITE_DATA( &tangentElementSize, sizeof(int) ); for( int i=0; i!=quads; ++i ) { short n[] = { 0, 32767, 0 }; WRITE_DATA( n, sizeof(short)*3 ); WRITE_DATA( n, sizeof(short)*3 ); WRITE_DATA( n, sizeof(short)*3 ); WRITE_DATA( n, sizeof(short)*3 ); } WRITE_DATA( &vertBiTangentID, sizeof(int) ); WRITE_DATA( &biTangentElementSize, sizeof(int) ); for( int i=0; i!=quads; ++i ) { short n[] = { 32767, 0, 0 }; WRITE_DATA( n, sizeof(short)*3 ); WRITE_DATA( n, sizeof(short)*3 ); WRITE_DATA( n, sizeof(short)*3 ); WRITE_DATA( n, sizeof(short)*3 ); } //Each vertex can be influenced by 4 joints - the joint IDs are written here WRITE_DATA( &vertJointIndexID, sizeof(int) ); WRITE_DATA( &jointIndexElementSize, sizeof(int) ); for( int i=0; i!=quads; ++i ) { char j[] = { 0, 0, 0, 0 }; WRITE_DATA( j, sizeof(char)*4 ); WRITE_DATA( j, sizeof(char)*4 ); WRITE_DATA( j, sizeof(char)*4 ); WRITE_DATA( j, sizeof(char)*4 ); } //The 'percent' (out of 255, not out of 100) that each of the above joints influences the vertex: WRITE_DATA( &vertJointWeightID, sizeof(int) ); WRITE_DATA( &jointWeightElementSize, sizeof(int) ); for( int i=0; i!=quads; ++i ) { ASSERT( sizeof(char) == 1 ) char j[] = { 255, 0, 0, 0 }; WRITE_DATA( j, sizeof(char)*4 ); WRITE_DATA( j, sizeof(char)*4 ); WRITE_DATA( j, sizeof(char)*4 ); WRITE_DATA( j, sizeof(char)*4 ); } */ //Tex-coords are pairs of floats WRITE_DATA( &vertTexCoordID, sizeof(int) ); WRITE_DATA( &texCoordElementSize, sizeof(int) ); for( int i=0; i!=quads; ++i ) { float uvTl[] = { 0.0f, 1.0f }; float uvBl[] = { 0.0f, 0.0f }; float uvBr[] = { 1.0f, 0.0f }; float uvTr[] = { 1.0f, 1.0f }; WRITE_DATA( uvTl, sizeof(float)*2 ); WRITE_DATA( uvBl, sizeof(float)*2 ); WRITE_DATA( uvBr, sizeof(float)*2 ); WRITE_DATA( uvTr, sizeof(float)*2 ); } /*! //You can have a second set of tex-coords if you want WRITE_DATA( &vertTexCoord2ID, sizeof(int) ); WRITE_DATA( &texCoord2ElementSize, sizeof(int) ); for( int i=0; i!=quads; ++i ) { float uvTl[] = { 0.0f, 1.0f }; float uvBl[] = { 0.0f, 0.0f }; float uvBr[] = { 1.0f, 0.0f }; float uvTr[] = { 1.0f, 1.0f }; WRITE_DATA( uvTl, sizeof(float)*2 ); WRITE_DATA( uvBl, sizeof(float)*2 ); WRITE_DATA( uvBr, sizeof(float)*2 ); WRITE_DATA( uvTr, sizeof(float)*2 ); }*/ //Finally, time for the index buffer WRITE_DATA( &numTriangleIndices, sizeof(int) ); for( int i=0; i!=quads; ++i ) { int base = i * 4; int a = base, b = base+1, c = base+2, d=base+2, e=base+3, f=base; WRITE_DATA( &a, sizeof(int) ); WRITE_DATA( &b, sizeof(int) ); WRITE_DATA( &c, sizeof(int) ); WRITE_DATA( &d, sizeof(int) ); WRITE_DATA( &e, sizeof(int) ); WRITE_DATA( &f, sizeof(int) ); } //Morph targets would go here, if I had any WRITE_DATA( &numMorphTargets, sizeof(int) ); ASSERT( written == fileSize );//ensure we didn't over/under-use the buffer }

Example Usage

// Build a geo H3DRes gridGeo = h3dAddResource( H3DResTypes::Geometry, "runtime/blahBlah.geo", H3DResFlags::NoQuery ); int batchStart = 0, batchCount = 0, vertRStart = 0, vertREnd = 0; { int dataSize = 0; char* data = 0; BuildLensBlurMesh( data, dataSize, batchStart, batchCount, vertRStart, vertREnd ); bool loadedData = h3dLoadResource( gridGeo, data, dataSize ); delete [] lensBlurData; } // Load a material H3DRes material = h3dAddResource( H3DResTypes::Material, "materials/grid.material.xml", 0 ); h3dutLoadResourcesFromDisk( _contentDir.c_str() ); // Create a model/mesh from the procedural geo H3DNode model = h3dAddModelNode( H3DRootNode, "MyModel", gridGeo ); H3DNode mesh = h3dAddMeshNode( model, "MyMesh", material, batchStart, batchCount, vertRStart, vertREnd );