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texture.c
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texture.c
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#include <stdlib.h>
#include <stdio.h>
#include <GL/glew.h>
#include "texture.h"
#include "utils.h"
#include "shaders_errors.h"
/* Based on: see LINKS: [3]. */
typedef
struct TgaHeader
{
int idlength:8;
int colormap:8;
int datatype:8;
int colormapinfo_1:8;
int colormapinfo_2:8;
int colormapinfo_3:8;
int colormapinfo_4:8;
int colormapinfo_5:8;
int xorigin:16;
int yorigin:16;
int width:16;
int height:16;
int bitperpel:8;
int description:8;
} __attribute__((packed))
TgaHeader;
GLuint createTexture(int w, int h, GLint format, const GLvoid * data)
{
GLuint textureId;
glGenTextures(1, &textureId);
glBindTexture(GL_TEXTURE_2D, textureId);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, format, w, h, 0,
GL_RGBA, GL_FLOAT, data);
glBindTexture(GL_TEXTURE_2D, 0);
return textureId;
}
GLuint createTextureFromTga(const char * path)
{
long length;
char * buffer = getTextFileContent(path, &length);
const TgaHeader * header = (TgaHeader *) buffer;
GLint format;
GLint internalFormat;
GLuint texture;
const GLvoid * imgData;
if (buffer == NULL)
{
return 0;
}
if (length <= (signed long) sizeof(TgaHeader))
{
fprintf(stderr, "Too small TGA file: %s\n", path);
free(buffer);
return 0;
}
if (header->datatype != 2 ||
(header->bitperpel != 24 && header->bitperpel != 32))
{
fprintf(stderr, "Wrong TGA file format: %s\n", path);
free(buffer);
return 0;
}
format = (header->bitperpel == 24 ? GL_BGR : GL_BGRA);
internalFormat = (format == GL_BGR ? GL_RGB8 : GL_RGBA8);
imgData = (const GLvoid *)
(buffer + sizeof(TgaHeader) + header->idlength);
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
/* Set 1-byte alignment (for non (2^n)x(2^n) size textures). */
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexImage2D(GL_TEXTURE_2D, 0, internalFormat,
header->width, header->height, 0, format,
GL_UNSIGNED_BYTE, imgData);
free(buffer);
#if 0
/* Linear filtering */
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
/*glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);*/
#else
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
#endif
#if 0
/* No wrap */
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
#else
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
#endif
CHECK_OPENGL_ERRORS(__FILE__, __LINE__);
return texture;
}
void freeTexture(GLuint texture)
{
glDeleteTextures(1, &texture);
}