| // |
| // Book: OpenGL(R) ES 2.0 Programming Guide |
| // Authors: Aaftab Munshi, Dan Ginsburg, Dave Shreiner |
| // ISBN-10: 0321502795 |
| // ISBN-13: 9780321502797 |
| // Publisher: Addison-Wesley Professional |
| // URLs: http://safari.informit.com/9780321563835 |
| // http://www.opengles-book.com |
| // |
| |
| // ESShapes.c |
| // |
| // Utility functions for generating shapes |
| // |
| |
| /// |
| // Includes |
| // |
| #include "esUtil.h" |
| #include <stdlib.h> |
| #include <math.h> |
| |
| /// |
| // Defines |
| // |
| #define ES_PI (3.14159265f) |
| |
| ////////////////////////////////////////////////////////////////// |
| // |
| // Private Functions |
| // |
| // |
| |
| |
| |
| ////////////////////////////////////////////////////////////////// |
| // |
| // Public Functions |
| // |
| // |
| |
| // |
| /// \brief Generates geometry for a sphere. Allocates memory for the vertex data and stores |
| /// the results in the arrays. Generate index list for a TRIANGLE_STRIP |
| /// \param numSlices The number of slices in the sphere |
| /// \param vertices If not NULL, will contain array of float3 positions |
| /// \param normals If not NULL, will contain array of float3 normals |
| /// \param texCoords If not NULL, will contain array of float2 texCoords |
| /// \param indices If not NULL, will contain the array of indices for the triangle strip |
| /// \return The number of indices required for rendering the buffers (the number of indices stored in the indices array |
| /// if it is not NULL ) as a GL_TRIANGLE_STRIP |
| // |
| int ESUTIL_API esGenSphere ( int numSlices, float radius, GLfloat **vertices, GLfloat **normals, |
| GLfloat **texCoords, GLushort **indices ) |
| { |
| int i; |
| int j; |
| int numParallels = numSlices / 2; |
| int numVertices = ( numParallels + 1 ) * ( numSlices + 1 ); |
| int numIndices = numParallels * numSlices * 6; |
| float angleStep = (2.0f * ES_PI) / ((float) numSlices); |
| |
| // Allocate memory for buffers |
| if ( vertices != NULL ) |
| *vertices = malloc ( sizeof(GLfloat) * 3 * numVertices ); |
| |
| if ( normals != NULL ) |
| *normals = malloc ( sizeof(GLfloat) * 3 * numVertices ); |
| |
| if ( texCoords != NULL ) |
| *texCoords = malloc ( sizeof(GLfloat) * 2 * numVertices ); |
| |
| if ( indices != NULL ) |
| *indices = malloc ( sizeof(GLushort) * numIndices ); |
| |
| for ( i = 0; i < numParallels + 1; i++ ) |
| { |
| for ( j = 0; j < numSlices + 1; j++ ) |
| { |
| int vertex = ( i * (numSlices + 1) + j ) * 3; |
| |
| if ( vertices ) |
| { |
| (*vertices)[vertex + 0] = radius * sinf ( angleStep * (float)i ) * |
| sinf ( angleStep * (float)j ); |
| (*vertices)[vertex + 1] = radius * cosf ( angleStep * (float)i ); |
| (*vertices)[vertex + 2] = radius * sinf ( angleStep * (float)i ) * |
| cosf ( angleStep * (float)j ); |
| } |
| |
| if ( normals ) |
| { |
| (*normals)[vertex + 0] = (*vertices)[vertex + 0] / radius; |
| (*normals)[vertex + 1] = (*vertices)[vertex + 1] / radius; |
| (*normals)[vertex + 2] = (*vertices)[vertex + 2] / radius; |
| } |
| |
| if ( texCoords ) |
| { |
| int texIndex = ( i * (numSlices + 1) + j ) * 2; |
| (*texCoords)[texIndex + 0] = (float) j / (float) numSlices; |
| (*texCoords)[texIndex + 1] = ( 1.0f - (float) i ) / (float) (numParallels - 1 ); |
| } |
| } |
| } |
| |
| // Generate the indices |
| if ( indices != NULL ) |
| { |
| GLushort *indexBuf = (*indices); |
| for ( i = 0; i < numParallels ; i++ ) |
| { |
| for ( j = 0; j < numSlices; j++ ) |
| { |
| *indexBuf++ = i * ( numSlices + 1 ) + j; |
| *indexBuf++ = ( i + 1 ) * ( numSlices + 1 ) + j; |
| *indexBuf++ = ( i + 1 ) * ( numSlices + 1 ) + ( j + 1 ); |
| |
| *indexBuf++ = i * ( numSlices + 1 ) + j; |
| *indexBuf++ = ( i + 1 ) * ( numSlices + 1 ) + ( j + 1 ); |
| *indexBuf++ = i * ( numSlices + 1 ) + ( j + 1 ); |
| } |
| } |
| } |
| |
| return numIndices; |
| } |
| |
| // |
| /// \brief Generates geometry for a cube. Allocates memory for the vertex data and stores |
| /// the results in the arrays. Generate index list for a TRIANGLES |
| /// \param scale The size of the cube, use 1.0 for a unit cube. |
| /// \param vertices If not NULL, will contain array of float3 positions |
| /// \param normals If not NULL, will contain array of float3 normals |
| /// \param texCoords If not NULL, will contain array of float2 texCoords |
| /// \param indices If not NULL, will contain the array of indices for the triangle strip |
| /// \return The number of indices required for rendering the buffers (the number of indices stored in the indices array |
| /// if it is not NULL ) as a GL_TRIANGLE_STRIP |
| // |
| int ESUTIL_API esGenCube ( float scale, GLfloat **vertices, GLfloat **normals, |
| GLfloat **texCoords, GLushort **indices ) |
| { |
| int i; |
| int numVertices = 24; |
| int numIndices = 36; |
| |
| GLfloat cubeVerts[] = |
| { |
| -0.5f, -0.5f, -0.5f, |
| -0.5f, -0.5f, 0.5f, |
| 0.5f, -0.5f, 0.5f, |
| 0.5f, -0.5f, -0.5f, |
| -0.5f, 0.5f, -0.5f, |
| -0.5f, 0.5f, 0.5f, |
| 0.5f, 0.5f, 0.5f, |
| 0.5f, 0.5f, -0.5f, |
| -0.5f, -0.5f, -0.5f, |
| -0.5f, 0.5f, -0.5f, |
| 0.5f, 0.5f, -0.5f, |
| 0.5f, -0.5f, -0.5f, |
| -0.5f, -0.5f, 0.5f, |
| -0.5f, 0.5f, 0.5f, |
| 0.5f, 0.5f, 0.5f, |
| 0.5f, -0.5f, 0.5f, |
| -0.5f, -0.5f, -0.5f, |
| -0.5f, -0.5f, 0.5f, |
| -0.5f, 0.5f, 0.5f, |
| -0.5f, 0.5f, -0.5f, |
| 0.5f, -0.5f, -0.5f, |
| 0.5f, -0.5f, 0.5f, |
| 0.5f, 0.5f, 0.5f, |
| 0.5f, 0.5f, -0.5f, |
| }; |
| |
| GLfloat cubeNormals[] = |
| { |
| 0.0f, -1.0f, 0.0f, |
| 0.0f, -1.0f, 0.0f, |
| 0.0f, -1.0f, 0.0f, |
| 0.0f, -1.0f, 0.0f, |
| 0.0f, 1.0f, 0.0f, |
| 0.0f, 1.0f, 0.0f, |
| 0.0f, 1.0f, 0.0f, |
| 0.0f, 1.0f, 0.0f, |
| 0.0f, 0.0f, -1.0f, |
| 0.0f, 0.0f, -1.0f, |
| 0.0f, 0.0f, -1.0f, |
| 0.0f, 0.0f, -1.0f, |
| 0.0f, 0.0f, 1.0f, |
| 0.0f, 0.0f, 1.0f, |
| 0.0f, 0.0f, 1.0f, |
| 0.0f, 0.0f, 1.0f, |
| -1.0f, 0.0f, 0.0f, |
| -1.0f, 0.0f, 0.0f, |
| -1.0f, 0.0f, 0.0f, |
| -1.0f, 0.0f, 0.0f, |
| 1.0f, 0.0f, 0.0f, |
| 1.0f, 0.0f, 0.0f, |
| 1.0f, 0.0f, 0.0f, |
| 1.0f, 0.0f, 0.0f, |
| }; |
| |
| GLfloat cubeTex[] = |
| { |
| 0.0f, 0.0f, |
| 0.0f, 1.0f, |
| 1.0f, 1.0f, |
| 1.0f, 0.0f, |
| 1.0f, 0.0f, |
| 1.0f, 1.0f, |
| 0.0f, 1.0f, |
| 0.0f, 0.0f, |
| 0.0f, 0.0f, |
| 0.0f, 1.0f, |
| 1.0f, 1.0f, |
| 1.0f, 0.0f, |
| 0.0f, 0.0f, |
| 0.0f, 1.0f, |
| 1.0f, 1.0f, |
| 1.0f, 0.0f, |
| 0.0f, 0.0f, |
| 0.0f, 1.0f, |
| 1.0f, 1.0f, |
| 1.0f, 0.0f, |
| 0.0f, 0.0f, |
| 0.0f, 1.0f, |
| 1.0f, 1.0f, |
| 1.0f, 0.0f, |
| }; |
| |
| // Allocate memory for buffers |
| if ( vertices != NULL ) |
| { |
| *vertices = malloc ( sizeof(GLfloat) * 3 * numVertices ); |
| memcpy( *vertices, cubeVerts, sizeof( cubeVerts ) ); |
| for ( i = 0; i < numVertices; i++ ) |
| { |
| (*vertices)[i] *= scale; |
| } |
| } |
| |
| if ( normals != NULL ) |
| { |
| *normals = malloc ( sizeof(GLfloat) * 3 * numVertices ); |
| memcpy( *normals, cubeNormals, sizeof( cubeNormals ) ); |
| } |
| |
| if ( texCoords != NULL ) |
| { |
| *texCoords = malloc ( sizeof(GLfloat) * 2 * numVertices ); |
| memcpy( *texCoords, cubeTex, sizeof( cubeTex ) ) ; |
| } |
| |
| |
| // Generate the indices |
| if ( indices != NULL ) |
| { |
| GLushort cubeIndices[] = |
| { |
| 0, 2, 1, |
| 0, 3, 2, |
| 4, 5, 6, |
| 4, 6, 7, |
| 8, 9, 10, |
| 8, 10, 11, |
| 12, 15, 14, |
| 12, 14, 13, |
| 16, 17, 18, |
| 16, 18, 19, |
| 20, 23, 22, |
| 20, 22, 21 |
| }; |
| |
| *indices = malloc ( sizeof(GLushort) * numIndices ); |
| memcpy( *indices, cubeIndices, sizeof( cubeIndices ) ); |
| } |
| |
| return numIndices; |
| } |