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#include "image.h"
struct imv_image {
int width; /* width of the image overall */
int height; /* height of the image overall */
int num_chunks; /* number of chunks allocated */
SDL_Texture **chunks; /* array of chunks */
int num_chunks_wide; /* number of chunks per row of the image */
int num_chunks_tall; /* number of chunks per column of the image */
int chunk_width; /* chunk width */
int chunk_height; /* chunk height */
int last_chunk_width; /* width of rightmost chunk */
int last_chunk_height; /* height of bottommost chunk */
SDL_Renderer *renderer; /* SDL renderer to draw to */
};
struct imv_image *imv_image_create(SDL_Renderer *r)
{
struct imv_image *image = malloc(sizeof(struct imv_image));
memset(image, 0, sizeof(struct imv_image));
image->renderer = r;
SDL_RendererInfo ri;
SDL_GetRendererInfo(r, &ri);
image->chunk_width = ri.max_texture_width != 0 ? ri.max_texture_width : 4096;
image->chunk_height = ri.max_texture_height != 0 ? ri.max_texture_height : 4096;
return image;
}
void imv_image_free(struct imv_image *image)
{
if(image->num_chunks > 0) {
for(int i = 0; i < image->num_chunks; ++i) {
SDL_DestroyTexture(image->chunks[i]);
}
free(image->chunks);
image->num_chunks = 0;
image->chunks = NULL;
image->renderer = NULL;
}
free(image);
}
int imv_image_set_bitmap(struct imv_image *image, struct imv_bitmap *bmp)
{
image->width = bmp->width;
image->height = bmp->height;
/* figure out how many chunks are needed, and create them */
if(image->num_chunks > 0) {
for(int i = 0; i < image->num_chunks; ++i) {
SDL_DestroyTexture(image->chunks[i]);
}
free(image->chunks);
}
image->num_chunks_wide = 1 + image->width / image->chunk_width;
image->num_chunks_tall = 1 + image->height / image->chunk_height;
image->last_chunk_width = image->width % image->chunk_width;
image->last_chunk_height = image->height % image->chunk_height;
if(image->last_chunk_width == 0) {
image->last_chunk_width = image->chunk_width;
}
if(image->last_chunk_height == 0) {
image->last_chunk_height = image->chunk_height;
}
image->num_chunks = image->num_chunks_wide * image->num_chunks_tall;
image->chunks = malloc(sizeof(SDL_Texture*) * image->num_chunks);
int failed_at = -1;
for(int y = 0; y < image->num_chunks_tall; ++y) {
for(int x = 0; x < image->num_chunks_wide; ++x) {
const int is_last_h_chunk = (x == image->num_chunks_wide - 1);
const int is_last_v_chunk = (y == image->num_chunks_tall - 1);
image->chunks[x + y * image->num_chunks_wide] =
SDL_CreateTexture(image->renderer,
SDL_PIXELFORMAT_ARGB8888,
SDL_TEXTUREACCESS_STATIC,
is_last_h_chunk ? image->last_chunk_width : image->chunk_width,
is_last_v_chunk ? image->last_chunk_height : image->chunk_height);
SDL_SetTextureBlendMode(image->chunks[x + y * image->num_chunks_wide],
SDL_BLENDMODE_BLEND);
if(image->chunks[x + y * image->num_chunks_wide] == NULL) {
failed_at = x + y * image->num_chunks_wide;
break;
}
}
}
if(failed_at != -1) {
for(int i = 0; i <= failed_at; ++i) {
SDL_DestroyTexture(image->chunks[i]);
}
free(image->chunks);
image->num_chunks = 0;
image->chunks = NULL;
return 1;
}
for(int y = 0; y < image->num_chunks_tall; ++y) {
for(int x = 0; x < image->num_chunks_wide; ++x) {
ptrdiff_t offset = 4 * x * image->chunk_width +
y * 4 * image->width * image->chunk_height;
unsigned char* addr = bmp->data + offset;
SDL_UpdateTexture(image->chunks[x + y * image->num_chunks_wide],
NULL, addr, 4 * image->width);
}
}
return 0;
}
void imv_image_draw(struct imv_image *image, int bx, int by, double scale)
{
int offset_x = 0;
int offset_y = 0;
for(int y = 0; y < image->num_chunks_tall; ++y) {
for(int x = 0; x < image->num_chunks_wide; ++x) {
int img_w, img_h;
SDL_QueryTexture(image->chunks[x + y * image->num_chunks_wide], NULL, NULL,
&img_w, &img_h);
SDL_Rect view_area = {
bx + offset_x,
by + offset_y,
img_w * scale,
img_h * scale
};
SDL_RenderCopy(image->renderer,
image->chunks[x + y * image->num_chunks_wide], NULL, &view_area);
offset_x += image->chunk_width * scale;
}
offset_x = 0;
offset_y += image->chunk_height * scale;
}
}
int imv_image_width(const struct imv_image *image)
{
return image->width;
}
int imv_image_height(const struct imv_image *image)
{
return image->height;
}
/* vim:set ts=2 sts=2 sw=2 et: */
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