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Sources/Classes/Model/OpenGL/Quad/GLQuad.m

/*

     File: GLQuad.m

 Abstract:

 Utility bass class for constructing a VBO quad.

  Version: 2.0

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 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

 THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS

 FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND

 OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

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*/

#pragma mark -

#pragma mark Private - Headers

#import "GLQuad.h"

#pragma mark -

#pragma mark Private - Data Structures

struct GLQuadData

    BOOL      resize;       // Flag to indicate if quad size changed

    GLuint    buffer;       // buffer identifier

    GLuint    count;        // vertex count

    GLuint    size;         // size of vertices or texture coordinates

    GLuint    capacity;     // vertex size + texture coordinate size

    GLsizei   stride;       // vbo stride

    GLenum    target;       // vbo target

    GLenum    usage;        // vbo usage

    GLenum    type;         // vbo type

    GLenum    mode;         // vbo mode

    GLfloat   width;        // quad width

    GLfloat   height;       // quad height

    GLfloat   aspect;       // aspect ratio

    GLfloat  *data;         // vbo data

    GLenum    quadType;     // vbo quad type

    GLfloat   vertices[8];  // Quad vertices

    GLfloat   texCoords[8]; // Quad texture coordinates

};

typedef struct GLQuadData  GLQuadData;

#pragma mark -

#pragma mark Private - Macros

#define BUFFER_OFFSET(i) ((GLchar *)NULL + (i))

#pragma mark -

#pragma mark Private - Accessors

static BOOL GLQuadSetSize(const NSSize *pSize,

                          GLQuadDataRef pQuad)

    BOOL bSuccess = (pSize != NULL);

    if(bSuccess)

        pQuad->resize = (pQuad->width != pSize->height) || (pQuad->width != pSize->height);

        if(pQuad->resize)

            pQuad->width  = pSize->width;

            pQuad->height = pSize->height;

            pQuad->aspect = pSize->width / pSize->height;

        } // if

    } // if

    else

        pQuad->width  = 1920.0f;

        pQuad->height = 1080.0f;

        pQuad->aspect = pQuad->width / pQuad->height;

    } // else

    return(bSuccess && pQuad->resize);

} // GLQuadSetSize

static void GLQuadSetDefaults(GLQuadDataRef pQuad)

    pQuad->count    = 4;

    pQuad->size     = 8 * sizeof(GLfloat);

    pQuad->capacity = 2 * pQuad->size;

    pQuad->usage    = GL_STATIC_DRAW;

    pQuad->type     = GL_FLOAT;

    pQuad->mode     = GL_QUADS;

    pQuad->target   = GL_ARRAY_BUFFER;

} // GLQuadSetDefaults

static BOOL GLQuadSetTextureCoordinates(const GLfloat *pTexCoords,

                                        GLQuadDataRef pQuad)

    BOOL success = pTexCoords != NULL;

    if(success)

        pQuad->texCoords[0] = pTexCoords[0];

        pQuad->texCoords[1] = pTexCoords[1];

        pQuad->texCoords[2] = pTexCoords[2];

        pQuad->texCoords[3] = pTexCoords[3];

        pQuad->texCoords[4] = pTexCoords[4];

        pQuad->texCoords[5] = pTexCoords[5],

        pQuad->texCoords[6] = pTexCoords[6];

        pQuad->texCoords[7] = pTexCoords[7];

    } // if

    return(success);

} // GLQuadSetTextureCoordinates

static BOOL GLQuadSetVertexArray(const GLfloat *pVertices,

                                 GLQuadDataRef pQuad)

    BOOL success = pVertices != NULL;

    if(success)

        pQuad->vertices[0] = pVertices[0];

        pQuad->vertices[1] = pVertices[1];

        pQuad->vertices[2] = pVertices[2];

        pQuad->vertices[3] = pVertices[3];

        pQuad->vertices[4] = pVertices[4];

        pQuad->vertices[5] = pVertices[5],

        pQuad->vertices[6] = pVertices[6];

        pQuad->vertices[7] = pVertices[7];

    } // if

    return(success);

} // GLQuadSetVertexArray

#pragma mark -

#pragma mark Private - Initializers

static void GLQuadInitArrays(GLQuadDataRef pQuad)

    pQuad->texCoords[0]  = 0.0f;

    pQuad->texCoords[1]  = 0.0f;

    pQuad->texCoords[2]  = 0.0f;

    pQuad->texCoords[3]  = 1.0f;

    pQuad->texCoords[4]  = 1.0f;

    pQuad->texCoords[5]  = 1.0f;

    pQuad->texCoords[6]  = 1.0f;

    pQuad->texCoords[7]  = 0.0f;

    pQuad->vertices[0]  = -1.0f;

    pQuad->vertices[1]  = -1.0f;

    pQuad->vertices[2]  = -1.0f;

    pQuad->vertices[3]  =  1.0f;

    pQuad->vertices[4]  =  1.0f;

    pQuad->vertices[5]  =  1.0f;

    pQuad->vertices[6]  =  1.0f;

    pQuad->vertices[7]  = -1.0f;

} // GLQuadInitArrays

#pragma mark -

#pragma mark Private - Constructor

static GLQuadDataRef GLQuadCreate(const NSSize *pSize,

                                  const GLenum target)

    GLQuadDataRef pQuad = (GLQuadDataRef)calloc(1, sizeof(GLQuadData));

    if(pQuad != NULL)

        GLQuadSetSize(pSize, pQuad);

        GLQuadSetDefaults(pQuad);

        GLQuadInitArrays(pQuad);

    } // if

    else

        NSLog(@">> ERROR: OpenGL Quad - Failure Allocating Memory For Data!");

    }  // else

    return(pQuad);

} // GLQuadCreate

#pragma mark -

#pragma mark Private - Destructors

static inline void GLQuadDeleteVertexBuffer(GLQuadDataRef pQuad)

    if(pQuad->buffer)

        glDeleteBuffers(1, &pQuad->buffer);

    } // if

} // GLQuadDeleteVertexBuffer

static void GLQuadDelete(GLQuadDataRef pQuad)

    if(pQuad != NULL)

        GLQuadDeleteVertexBuffer(pQuad);

        free(pQuad);

        pQuad = NULL;

    } // if

} // GLQuadDelete

#pragma mark -

#pragma mark Private - Utilities

static BOOL GLQuadAcquire(GLQuadDataRef pQuad)

    if(!pQuad->buffer)

        glGenBuffers(1, &pQuad->buffer);

        if(pQuad->buffer)

            glBindBuffer(pQuad->target, pQuad->buffer);

                glBufferData(pQuad->target, pQuad->capacity, NULL, pQuad->usage);

                glBufferSubData(pQuad->target, 0, pQuad->size, pQuad->vertices);

                glBufferSubData(pQuad->target, pQuad->size, pQuad->size, pQuad->texCoords);

                glVertexPointer(2, pQuad->type, pQuad->stride, BUFFER_OFFSET(0));

                glTexCoordPointer(2, pQuad->type, pQuad->stride, BUFFER_OFFSET(pQuad->size));

            glBindBuffer(pQuad->target, 0);

        } // if

    } // if

    return(pQuad->buffer != 0);

} // GLQuadAcquire

static BOOL GLQuadUpdate(GLQuadDataRef pQuad)

    BOOL bSuccess = pQuad->resize;

    if(bSuccess)

        glBindBuffer(pQuad->target,

                     pQuad->buffer);

            glBufferData(pQuad->target,

                         pQuad->capacity,

                         NULL,

                         pQuad->usage);

            pQuad->data = (GLfloat *)glMapBuffer(pQuad->target, GL_WRITE_ONLY);

            if(pQuad->data != NULL)

                // Vertices

                pQuad->data[0] = pQuad->vertices[0];

                pQuad->data[1] = pQuad->vertices[1];

                pQuad->data[2] = pQuad->vertices[2];

                pQuad->data[3] = pQuad->vertices[3];

                pQuad->data[4] = pQuad->vertices[4];

                pQuad->data[5] = pQuad->vertices[5],

                pQuad->data[6] = pQuad->vertices[6];

                pQuad->data[7] = pQuad->vertices[7];

                // Texture coordinates

                pQuad->data[8]  = pQuad->texCoords[0];

                pQuad->data[9]  = pQuad->texCoords[1];

                pQuad->data[10] = pQuad->texCoords[2];

                pQuad->data[11] = pQuad->texCoords[3];

                pQuad->data[12] = pQuad->texCoords[4];

                pQuad->data[13] = pQuad->texCoords[5],

                pQuad->data[14] = pQuad->texCoords[6];

                pQuad->data[15] = pQuad->texCoords[7];

            } // if

            bSuccess = glUnmapBuffer(pQuad->target);

        glBindBuffer(pQuad->target, 0);

    } // if

    return(bSuccess);

} // GLQuadUpdate

static void GLQuadDisplay(GLQuadDataRef pQuad)

    glBindBuffer(pQuad->target, pQuad->buffer);

        glPushMatrix();

            glScalef(pQuad->aspect, 1.0f, 1.0f);

            glDrawArrays(pQuad->mode, 0, pQuad->count);

        glPopMatrix();

    glBindBuffer(pQuad->target, 0);

} // GLQuadDisplay

#pragma mark -

@implementation GLQuad

#pragma mark -

#pragma mark Public - Designated Initializer

// Initialize

- (id) init

    self = [super init];

    if(self)

        mpQuad = GLQuadCreate(NULL, GL_TEXTURE_2D);

    } // if

    return(self);

} // init

- (id) initQuadWithSize:(const NSSize *)theSize

                 target:(const GLenum)theTarget

    self = [super init];

    if(self)

        mpQuad = GLQuadCreate(theSize, theTarget);

    } // if

    return(self);

} // initQuadWithSize

#pragma mark -

#pragma mark Public - Destructor

- (void) dealloc

    GLQuadDelete(mpQuad);

    [super dealloc];

} // dealloc

#pragma mark -

#pragma mark Public - Accessors - Getters

- (GLuint) buffer

    return(mpQuad->buffer);

} // buffer

- (GLuint) count

    return(mpQuad->count);

} // count

- (GLuint) size

    return(mpQuad->size);

} // size

- (GLenum) target

    return(mpQuad->target);

} // target

- (GLenum) type

    return(mpQuad->type);

} // type

- (GLenum) mode

    return(mpQuad->mode);

} // mode

- (GLsizei) stride

    return(mpQuad->stride);

} // stride

- (GLfloat) aspect

    return(mpQuad->aspect);

} // aspect

- (GLfloat) width

    return(mpQuad->width);

} // aspect

- (GLfloat) height

    return(mpQuad->height);

} // height

#pragma mark -

#pragma mark Public - Accessors - Setters

- (BOOL) setTexCoords:(const GLfloat *)theTexCoords

    return(GLQuadSetTextureCoordinates(theTexCoords, mpQuad));

} // setTexCoords

- (BOOL) setVertices:(const GLfloat *)theVertices

    return(GLQuadSetVertexArray(theVertices, mpQuad));

} // setVertices

- (BOOL) setSize:(const NSSize *)theSize

    return(GLQuadSetSize(theSize, mpQuad));

} // setSize

#pragma mark -

#pragma mark Public - Utilities

- (BOOL) acquire

    return(GLQuadAcquire(mpQuad));

} // acquire

- (BOOL) update

    return(GLQuadUpdate(mpQuad));

} // update

// Draw a quad using texture & vertex coordinates

- (void) display

    GLQuadDisplay(mpQuad);

} // display

@end

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