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#include "../../include/mgl/graphics/texture.h"
#include "../../include/mgl/graphics/image.h"
#include "../../include/mgl/mgl.h"
#include <stdio.h>
/* TODO: Check for glTexImage2D/glTexSubImage2D failure */
static int mgl_texture_format_to_opengl_format(mgl_texture_format format) {
switch(format) {
case MGL_TEXTURE_FORMAT_ALPHA: return GL_ALPHA8;
case MGL_TEXTURE_FORMAT_GRAY: return GL_LUMINANCE8;
case MGL_TEXTURE_FORMAT_GRAY_ALPHA: return GL_LUMINANCE8_ALPHA8;
case MGL_TEXTURE_FORMAT_RGB: return GL_RGB8;
case MGL_TEXTURE_FORMAT_RGBA: return GL_RGBA8;
}
return 0;
}
static int mgl_texture_format_to_compressed_opengl_format(mgl_texture_format format) {
switch(format) {
case MGL_TEXTURE_FORMAT_ALPHA: return GL_ALPHA8;
case MGL_TEXTURE_FORMAT_GRAY: return GL_LUMINANCE8;
case MGL_TEXTURE_FORMAT_GRAY_ALPHA: return GL_LUMINANCE8_ALPHA8;
case MGL_TEXTURE_FORMAT_RGB: return GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
case MGL_TEXTURE_FORMAT_RGBA: return GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
}
return 0;
}
static int mgl_texture_format_to_source_opengl_format(mgl_texture_format format) {
switch(format) {
case MGL_TEXTURE_FORMAT_ALPHA: return GL_ALPHA;
case MGL_TEXTURE_FORMAT_GRAY: return GL_LUMINANCE;
case MGL_TEXTURE_FORMAT_GRAY_ALPHA: return GL_LUMINANCE_ALPHA;
case MGL_TEXTURE_FORMAT_RGB: return GL_RGB;
case MGL_TEXTURE_FORMAT_RGBA: return GL_RGBA;
}
return 0;
}
static mgl_texture_format mgl_image_format_to_mgl_texture_format(mgl_image_format image_format) {
switch(image_format) {
case MGL_IMAGE_FORMAT_ALPHA: return MGL_TEXTURE_FORMAT_ALPHA;
case MGL_IMAGE_FORMAT_GRAY: return MGL_TEXTURE_FORMAT_GRAY;
case MGL_IMAGE_FORMAT_GRAY_ALPHA: return MGL_TEXTURE_FORMAT_GRAY_ALPHA;
case MGL_IMAGE_FORMAT_RGB: return MGL_TEXTURE_FORMAT_RGB;
case MGL_IMAGE_FORMAT_RGBA: return MGL_TEXTURE_FORMAT_RGBA;
}
return 0;
}
int mgl_texture_init(mgl_texture *self) {
self->id = 0;
self->width = 0;
self->height = 0;
self->format = 0;
self->max_width = 0;
self->max_height = 0;
self->pixel_coordinates = false;
mgl_context *context = mgl_get_context();
context->gl.glGenTextures(1, &self->id);
if(self->id == 0) {
fprintf(stderr, "Error: failed to init texture (glGenTextures failed)\n");
return -1;
}
int max_texture_size = 0;
context->gl.glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max_texture_size);
self->max_width = max_texture_size;
self->max_height = max_texture_size;
return 0;
}
int mgl_texture_load_from_file(mgl_texture *self, const char *filepath, mgl_texture_load_options *load_options) {
mgl_image image;
if(mgl_image_load_from_file(&image, filepath) != 0)
return -1;
int result = mgl_texture_load_from_image(self, &image, load_options);
mgl_image_unload(&image);
return result;
}
int mgl_texture_load_from_image(mgl_texture *self, const mgl_image *image, mgl_texture_load_options *load_options) {
return mgl_texture_load_from_memory(self, image->data, image->width, image->height, image->format, load_options);
}
int mgl_texture_load_from_memory(mgl_texture *self, const unsigned char *data, int width, int height, mgl_image_format format, mgl_texture_load_options *load_options) {
if(width < 0 || height < 0)
return -1;
if(width > self->max_width || height > self->max_height)
return -1;
self->width = width;
self->height = height;
self->format = mgl_image_format_to_mgl_texture_format(format);
self->pixel_coordinates = load_options ? load_options->pixel_coordinates : false;
int opengl_texture_format = mgl_texture_format_to_opengl_format(self->format);
if(load_options && load_options->compressed)
opengl_texture_format = mgl_texture_format_to_compressed_opengl_format(self->format);
mgl_context *context = mgl_get_context();
context->gl.glBindTexture(GL_TEXTURE_2D, self->id);
context->gl.glTexImage2D(GL_TEXTURE_2D, 0, opengl_texture_format, self->width, self->height, 0, mgl_texture_format_to_source_opengl_format(self->format), GL_UNSIGNED_BYTE, data);
context->gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
context->gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
context->gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
context->gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
context->gl.glBindTexture(GL_TEXTURE_2D, 0);
return 0;
}
int mgl_texture_update(mgl_texture *self, const unsigned char *data, int offset_x, int offset_y, int width, int height, mgl_image_format format) {
if(offset_x + width > self->width || offset_y + height > self->height)
return -1;
mgl_context *context = mgl_get_context();
context->gl.glBindTexture(GL_TEXTURE_2D, self->id);
const mgl_texture_format texture_format = mgl_image_format_to_mgl_texture_format(format);
/* TODO: TODO: Only do one glTexSubImage2D */
#if 1
for(int i = 0; i < height; ++i) {
context->gl.glTexSubImage2D(GL_TEXTURE_2D, 0, offset_x, offset_y + i, width, 1, mgl_texture_format_to_source_opengl_format(texture_format), GL_UNSIGNED_BYTE, data + (i * width));
}
#else
context->gl.glTexSubImage2D(GL_TEXTURE_2D, 0, offset_x, offset_y, width, height, mgl_texture_format_to_source_opengl_format(texture_format), GL_UNSIGNED_BYTE, data);
#endif
context->gl.glBindTexture(GL_TEXTURE_2D, 0);
return 0;
}
int mgl_texture_resize(mgl_texture *self, int new_width, int new_height, mgl_texture_load_options *load_options) {
if(new_width == self->width && new_height == self->height)
return 0;
if(new_width < 0 || new_height < 0)
return -1;
if(new_width > self->max_width || new_height > self->max_height)
return -1;
self->width = new_width;
self->height = new_height;
const int opengl_texture_format = load_options && load_options->compressed ? mgl_texture_format_to_compressed_opengl_format(self->format) : mgl_texture_format_to_opengl_format(self->format);
mgl_context *context = mgl_get_context();
context->gl.glBindTexture(GL_TEXTURE_2D, self->id);
context->gl.glTexImage2D(GL_TEXTURE_2D, 0, opengl_texture_format, self->width, self->height, 0, mgl_texture_format_to_source_opengl_format(self->format), GL_UNSIGNED_BYTE, NULL);
context->gl.glBindTexture(GL_TEXTURE_2D, 0);
return 0;
}
void mgl_texture_use(const mgl_texture *texture) {
mgl_context *context = mgl_get_context();
if(texture) {
float matrix[16] = {
1.0f, 0.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f,
};
if(texture->pixel_coordinates) {
matrix[0] = 1.0f / (float)texture->width;
matrix[5] = 1.0f / (float)texture->height;
}
context->gl.glMatrixMode(GL_TEXTURE);
context->gl.glLoadMatrixf(matrix);
context->gl.glMatrixMode(GL_MODELVIEW);
context->gl.glBindTexture(GL_TEXTURE_2D, texture->id);
} else {
context->gl.glBindTexture(GL_TEXTURE_2D, 0);
}
}
void mgl_texture_unload(mgl_texture *self) {
mgl_context *context = mgl_get_context();
if(self->id) {
context->gl.glDeleteTextures(1, &self->id);
self->id = 0;
}
}
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