added libimago
[eradicate] / libs / imago / src / imago_gl.c
diff --git a/libs/imago/src/imago_gl.c b/libs/imago/src/imago_gl.c
new file mode 100644 (file)
index 0000000..7dc444d
--- /dev/null
@@ -0,0 +1,235 @@
+#include "imago2.h"
+
+/* to avoid dependency to OpenGL, I'll define all the relevant GL macros manually */
+#define GL_UNSIGNED_BYTE               0x1401
+#define GL_FLOAT                               0x1406
+
+#define GL_LUMINANCE                   0x1909
+#define GL_RGB                                 0x1907
+#define GL_RGBA                                        0x1908
+
+#define GL_RGBA32F                             0x8814
+#define GL_RGB32F                              0x8815
+#define GL_LUMINANCE32F                        0x8818
+
+#define GL_TEXTURE_2D                  0x0de1
+#define GL_TEXTURE_WRAP_S              0x2802
+#define GL_TEXTURE_WRAP_T              0x2803
+#define GL_TEXTURE_MAG_FILTER  0x2800
+#define GL_TEXTURE_MIN_FILTER  0x2801
+#define GL_LINEAR                              0x2601
+#define GL_REPEAT                              0x2901
+
+
+typedef unsigned int GLenum;
+typedef unsigned int GLuint;
+typedef int GLint;
+typedef int GLsizei;
+typedef void GLvoid;
+
+/* for the same reason I'll load GL functions dynamically */
+#ifndef WIN32
+typedef void (*gl_gen_textures_func)(GLsizei, GLuint*);
+typedef void (*gl_bind_texture_func)(GLenum, GLuint);
+typedef void (*gl_tex_parameteri_func)(GLenum, GLenum, GLint);
+typedef void (*gl_tex_image2d_func)(GLenum, GLint, GLint, GLsizei, GLsizei, GLint, GLenum, GLenum, const GLvoid*);
+#else
+typedef void (__stdcall *gl_gen_textures_func)(GLsizei, GLuint*);
+typedef void (__stdcall *gl_bind_texture_func)(GLenum, GLuint);
+typedef void (__stdcall *gl_tex_parameteri_func)(GLenum, GLenum, GLint);
+typedef void (__stdcall *gl_tex_image2d_func)(GLenum, GLint, GLint, GLsizei, GLsizei, GLint, GLenum, GLenum, const GLvoid*);
+#endif
+
+static gl_gen_textures_func gl_gen_textures;
+static gl_bind_texture_func gl_bind_texture;
+static gl_tex_parameteri_func gl_tex_parameteri;
+static gl_tex_image2d_func gl_tex_image2d;
+
+static int load_glfunc(void);
+
+unsigned int img_fmt_glfmt(enum img_fmt fmt)
+{
+       switch(fmt) {
+       case IMG_FMT_GREY8:
+       case IMG_FMT_GREYF:
+               return GL_LUMINANCE;
+
+       case IMG_FMT_RGB24:
+       case IMG_FMT_RGBF:
+               return GL_RGB;
+
+       case IMG_FMT_RGBA32:
+       case IMG_FMT_RGBAF:
+               return GL_RGBA;
+
+       default:
+               break;
+       }
+       return 0;
+}
+
+unsigned int img_fmt_gltype(enum img_fmt fmt)
+{
+       switch(fmt) {
+       case IMG_FMT_GREY8:
+       case IMG_FMT_RGB24:
+       case IMG_FMT_RGBA32:
+               return GL_UNSIGNED_BYTE;
+
+       case IMG_FMT_GREYF:
+       case IMG_FMT_RGBF:
+       case IMG_FMT_RGBAF:
+               return GL_FLOAT;
+
+       default:
+               break;
+       }
+       return 0;
+}
+
+unsigned int img_fmt_glintfmt(enum img_fmt fmt)
+{
+       switch(fmt) {
+       case IMG_FMT_GREY8:
+               return GL_LUMINANCE;
+       case IMG_FMT_RGB24:
+               return GL_RGB;
+       case IMG_FMT_RGBA32:
+               return GL_RGBA;
+       case IMG_FMT_GREYF:
+               return GL_LUMINANCE32F;
+       case IMG_FMT_RGBF:
+               return GL_RGB32F;
+       case IMG_FMT_RGBAF:
+               return GL_RGBA32F;
+       default:
+               break;
+       }
+       return 0;
+}
+
+unsigned int img_glfmt(struct img_pixmap *img)
+{
+       return img_fmt_glfmt(img->fmt);
+}
+
+unsigned int img_gltype(struct img_pixmap *img)
+{
+       return img_fmt_gltype(img->fmt);
+}
+
+unsigned int img_glintfmt(struct img_pixmap *img)
+{
+       return img_fmt_glintfmt(img->fmt);
+}
+
+unsigned int img_gltexture(struct img_pixmap *img)
+{
+       unsigned int tex;
+       unsigned int intfmt, fmt, type;
+
+       if(!gl_gen_textures) {
+               if(load_glfunc() == -1) {
+                       fprintf(stderr, "imago: failed to initialize the OpenGL helpers\n");
+                       return 0;
+               }
+       }
+
+       intfmt = img_glintfmt(img);
+       fmt = img_glfmt(img);
+       type = img_gltype(img);
+
+       gl_gen_textures(1, &tex);
+       gl_bind_texture(GL_TEXTURE_2D, tex);
+       gl_tex_parameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+       gl_tex_parameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+       gl_tex_parameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+       gl_tex_parameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+       gl_tex_image2d(GL_TEXTURE_2D, 0, intfmt, img->width, img->height, 0, fmt, type, img->pixels);
+       return tex;
+}
+
+unsigned int img_gltexture_load(const char *fname)
+{
+       struct img_pixmap img;
+       unsigned int tex;
+
+       img_init(&img);
+       if(img_load(&img, fname) == -1) {
+               img_destroy(&img);
+               return 0;
+       }
+
+       tex = img_gltexture(&img);
+       img_destroy(&img);
+       return tex;
+}
+
+unsigned int img_gltexture_read_file(FILE *fp)
+{
+       struct img_pixmap img;
+       unsigned int tex;
+
+       img_init(&img);
+       if(img_read_file(&img, fp) == -1) {
+               img_destroy(&img);
+               return 0;
+       }
+
+       tex = img_gltexture(&img);
+       img_destroy(&img);
+       return tex;
+}
+
+unsigned int img_gltexture_read(struct img_io *io)
+{
+       struct img_pixmap img;
+       unsigned int tex;
+
+       img_init(&img);
+       if(img_read(&img, io) == -1) {
+               img_destroy(&img);
+               return 0;
+       }
+
+       tex = img_gltexture(&img);
+       img_destroy(&img);
+       return tex;
+}
+
+#if (defined(__DOS__) || defined(__MSDOS__)) && defined(__unix__)
+#undef __unix__
+#endif
+
+#if defined(__unix__) || defined(__APPLE__)
+#ifndef __USE_GNU
+#define __USE_GNU
+#endif
+
+#include <dlfcn.h>
+#endif
+#ifdef WIN32
+#include <windows.h>
+#endif
+
+static int load_glfunc(void)
+{
+#if defined(__unix__) || defined(__APPLE__)
+       gl_gen_textures = (gl_gen_textures_func)dlsym(RTLD_DEFAULT, "glGenTextures");
+       gl_bind_texture = (gl_bind_texture_func)dlsym(RTLD_DEFAULT, "glBindTexture");
+       gl_tex_parameteri = (gl_tex_parameteri_func)dlsym(RTLD_DEFAULT, "glTexParameteri");
+       gl_tex_image2d = (gl_tex_image2d_func)dlsym(RTLD_DEFAULT, "glTexImage2D");
+#endif
+
+#ifdef WIN32
+       HANDLE dll = LoadLibrary("opengl32.dll");
+       if(dll) {
+               gl_gen_textures = (gl_gen_textures_func)GetProcAddress(dll, "glGenTextures");
+               gl_bind_texture = (gl_bind_texture_func)GetProcAddress(dll, "glBindTexture");
+               gl_tex_parameteri = (gl_tex_parameteri_func)GetProcAddress(dll, "glTexParameteri");
+               gl_tex_image2d = (gl_tex_image2d_func)GetProcAddress(dll, "glTexImage2D");
+       }
+#endif
+
+       return (gl_gen_textures && gl_bind_texture && gl_tex_parameteri && gl_tex_image2d) ? 0 : -1;
+}