Permalink
Switch branches/tags
Nothing to show
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
281 lines (250 sloc) 7.61 KB
//
// 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>
#include <string.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, GLuint **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(GLuint) * 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 )
{
GLuint *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, GLuint **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 * 3; 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 )
{
GLuint 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(GLuint) * numIndices );
memcpy( *indices, cubeIndices, sizeof( cubeIndices ) );
}
return numIndices;
}