Add imv_texture object

2 files changed, 151 insertions, 0 deletions

diff --git a/texture.c b/texture.c
new file mode 100644
index 0000000..3145344
--- /dev/null
+++ b/texture.c
@@ -0,0 +1,124 @@
+#include "texture.h"
+
+void imv_init_texture(struct imv_texture *tex, SDL_Renderer *r)
+{
+  tex->renderer = r;
+  tex->num_chunks = 0;
+  tex->chunks = NULL;
+
+  SDL_RendererInfo ri;
+  SDL_GetRendererInfo(r, &ri);
+  tex->chunk_width = ri.max_texture_width;
+  tex->chunk_height = ri.max_texture_height;
+}
+
+void imv_destroy_texture(struct imv_texture *tex)
+{
+  if(tex->num_chunks > 0) {
+    for(int i = 0; i < tex->num_chunks; ++i) {
+      SDL_DestroyTexture(tex->chunks[i]);
+    }
+    free(tex->chunks);
+    tex->num_chunks = 0;
+    tex->chunks = NULL;
+    tex->renderer = NULL;
+  }
+}
+
+int imv_texture_set_image(struct imv_texture *tex, FIBITMAP *image)
+{
+  FIBITMAP *frame = FreeImage_ConvertTo32Bits(image);
+  tex->width = FreeImage_GetWidth(frame);
+  tex->height = FreeImage_GetHeight(frame);
+
+  char* pixels = (char*)FreeImage_GetBits(frame);
+
+  //figure out how many chunks are needed, and create them
+  if(tex->num_chunks > 0) {
+    for(int i = 0; i < tex->num_chunks; ++i) {
+      SDL_DestroyTexture(tex->chunks[i]);
+    }
+    free(tex->chunks);
+  }
+
+  tex->num_chunks_wide = 1 + tex->width / tex->chunk_width;
+  tex->num_chunks_tall = 1 + tex->height / tex->chunk_height;
+
+  tex->last_chunk_width = tex->width % tex->chunk_width;
+  tex->last_chunk_height = tex->height % tex->chunk_height;
+
+  if(tex->last_chunk_width == 0) {
+    tex->last_chunk_width = tex->chunk_width;
+  }
+  if(tex->last_chunk_height == 0) {
+    tex->last_chunk_height = tex->chunk_height;
+  }
+
+  tex->num_chunks = tex->num_chunks_wide * tex->num_chunks_tall;
+  tex->chunks = (SDL_Texture**)malloc(sizeof(SDL_Texture*) * tex->num_chunks);
+
+  int failed_at = -1;
+  for(int y = 0; y < tex->num_chunks_tall; ++y) {
+    for(int x = 0; x < tex->num_chunks_wide; ++x) {
+      const int is_last_h_chunk = (x == tex->num_chunks_wide - 1);
+      const int is_last_v_chunk = (y == tex->num_chunks_tall - 1);
+      tex->chunks[x + y * tex->num_chunks_wide] =
+        SDL_CreateTexture(tex->renderer,
+          SDL_PIXELFORMAT_RGB888,
+          SDL_TEXTUREACCESS_STATIC,
+          is_last_h_chunk ? tex->last_chunk_width : tex->chunk_width,
+          is_last_v_chunk ? tex->last_chunk_height : tex->chunk_height);
+      if(tex->chunks[x + y * tex->num_chunks_wide] == NULL) {
+        failed_at = x + y * tex->num_chunks_wide;
+        break;
+      }
+    }
+  }
+
+  if(failed_at != -1) {
+    for(int i = 0; i <= failed_at; ++i) {
+      SDL_DestroyTexture(tex->chunks[i]);
+    }
+    free(tex->chunks);
+    tex->num_chunks = 0;
+    tex->chunks = NULL;
+    return 1;
+  }
+
+  for(int y = 0; y < tex->num_chunks_tall; ++y) {
+    for(int x = 0; x < tex->num_chunks_wide; ++x) {
+      ptrdiff_t offset = 4 * x * tex->chunk_width +
+        y * 4 * tex->width * tex->chunk_height;
+      char* addr = pixels + offset;
+      SDL_UpdateTexture(tex->chunks[x + y * tex->num_chunks_wide],
+          NULL, addr, 4 * tex->width);
+    }
+  }
+
+  return 0;
+}
+
+void imv_texture_draw(struct imv_texture *tex, int bx, int by, double scale)
+{
+  int offset_x = 0;
+  int offset_y = 0;
+  for(int y = 0; y < tex->num_chunks_tall; ++y) {
+    for(int x = 0; x < tex->num_chunks_wide; ++x) {
+      int img_w, img_h, img_access;
+      unsigned int img_format;
+      SDL_QueryTexture(tex->chunks[x + y * tex->num_chunks_wide],
+          &img_format, &img_access, &img_w, &img_h);
+      SDL_Rect view_area = {
+        bx + offset_x,
+        by + offset_y,
+        img_w * scale,
+        img_h * scale
+      };
+      SDL_RenderCopy(tex->renderer,
+          tex->chunks[x + y * tex->num_chunks_wide], NULL, &view_area);
+      offset_x += tex->chunk_width * scale;
+    }
+    offset_x = 0;
+    offset_y += tex->chunk_height * scale;
+  }
+}
diff --git a/texture.h b/texture.h
new file mode 100644
index 0000000..cae0d33
--- /dev/null
+++ b/texture.h
@@ -0,0 +1,27 @@
+#ifndef IMV_TEXTURE_H
+#define IMV_TEXTURE_H
+
+#include <SDL2/SDL.h>
+#include <FreeImage.h>
+
+struct imv_texture {
+  int width;              //width of the texture overall
+  int height;             //height of the texture 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
+};
+
+void imv_init_texture(struct imv_texture *tex, SDL_Renderer *r);
+void imv_destroy_texture(struct imv_texture *tex);
+
+int imv_texture_set_image(struct imv_texture *tex, FIBITMAP *image);
+void imv_texture_draw(struct imv_texture *tex, int x, int y, double scale);
+
+#endif