twn_skybox.c

src/rendering/twn_gl_15_rendering.c

@@ -1,5 +1,6 @@
 #include "twn_rendering_c.h"
 #include "twn_util.h"
+#include "twn_util_c.h"
 #include "twn_config.h"
 #include "twn_engine_context_c.h"
 #include "twn_text_c.h"
@@ -464,3 +465,152 @@ void finally_draw_text(FontData const *font_data,
 size_t get_text_payload_size(void) {
     return sizeof (ElementIndexedQuadWithoutColor);
 }
+
+static void load_cubemap_side(const char *path, GLenum target) {
+    SDL_Surface *surface = textures_load_surface(path);
+    /* TODO: sanity check whether all of them have same dimensions? */
+    glTexImage2D(target,
+                 0,
+                 GL_RGBA8,
+                 surface->w, surface->h,
+                 0,
+                 surface->format->BytesPerPixel == 4 ? GL_RGBA : GL_RGB,
+                 GL_UNSIGNED_BYTE,
+                 surface->pixels);
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
+
+    SDL_free(surface->pixels);
+    SDL_FreeSurface(surface);
+}
+
+void finally_render_skybox(char *paths) {
+    static GLuint cubemap = 0;
+    static char *paths_cache = NULL;
+
+    bool loading_needed = false;
+
+    /* drop it */
+    if (!paths_cache || (SDL_strcmp(paths_cache, paths) != 0)) {
+        if (cubemap)
+            glDeleteTextures(1, &cubemap);
+        glGenTextures(1, &cubemap);
+        if (paths_cache)
+            SDL_free(paths_cache);
+        paths_cache = paths;
+        loading_needed = true;
+    }
+
+    Matrix4 camera_look_at_matrix_solipsist = camera_look_at_matrix;
+    camera_look_at_matrix_solipsist.row[3].x = 0;
+    camera_look_at_matrix_solipsist.row[3].y = 0;
+    camera_look_at_matrix_solipsist.row[3].z = 0;
+
+    glMatrixMode(GL_MODELVIEW);
+    glLoadMatrixf(&camera_look_at_matrix_solipsist.row[0].x);
+
+    glDisable(GL_TEXTURE_2D);
+    glEnable(GL_TEXTURE_CUBE_MAP);
+    glBindTexture(GL_TEXTURE_CUBE_MAP, cubemap);
+
+    /* note: assumes that space pipeline is applied already */
+    glDisable(GL_ALPHA_TEST);
+    glDepthMask(GL_TRUE);
+
+    if (loading_needed) {
+        /* load all the sides */
+        char *expanded = expand_asterisk(paths, "up");
+        load_cubemap_side(expanded,  GL_TEXTURE_CUBE_MAP_POSITIVE_Y);
+        SDL_free(expanded);
+
+        expanded = expand_asterisk(paths, "down");
+        load_cubemap_side(expanded,  GL_TEXTURE_CUBE_MAP_NEGATIVE_Y);
+        SDL_free(expanded);
+
+        expanded = expand_asterisk(paths, "east");
+        load_cubemap_side(expanded,  GL_TEXTURE_CUBE_MAP_POSITIVE_X);
+        SDL_free(expanded);
+
+        expanded = expand_asterisk(paths, "north");
+        load_cubemap_side(expanded,  GL_TEXTURE_CUBE_MAP_POSITIVE_Z);
+        SDL_free(expanded);
+
+        expanded = expand_asterisk(paths, "west");
+        load_cubemap_side(expanded,  GL_TEXTURE_CUBE_MAP_NEGATIVE_X);
+        SDL_free(expanded);
+
+        expanded = expand_asterisk(paths, "south");
+        load_cubemap_side(expanded,  GL_TEXTURE_CUBE_MAP_NEGATIVE_Z);
+        SDL_free(expanded);
+    }
+
+    /* TODO: use lists at the very least */
+    /* TODO: figure out which coordinates to use to not have issues with far z */
+
+    glBegin(GL_QUADS); {
+        /* up */
+        glTexCoord3f(50.f, 50.f, 50.f);
+        glVertex3f(50.f, 50.f, 50.f);
+        glTexCoord3f(-50.f, 50.f, 50.f);
+        glVertex3f(-50.f, 50.f, 50.f);
+        glTexCoord3f(-50.f, 50.f, -50.f);
+        glVertex3f(-50.f, 50.f, -50.f);
+        glTexCoord3f(50.f, 50.f, -50.f);
+        glVertex3f(50.f, 50.f, -50.f);
+
+        /* down */
+        glTexCoord3f(50.f, -50.f, 50.f);
+        glVertex3f(50.f, -50.f, 50.f);
+        glTexCoord3f(50.f, -50.f, -50.f);
+        glVertex3f(50.f, -50.f, -50.f);
+        glTexCoord3f(-50.f, -50.f, -50.f);
+        glVertex3f(-50.f, -50.f, -50.f);
+        glTexCoord3f(-50.f, -50.f, 50.f);
+        glVertex3f(-50.f, -50.f, 50.f);
+
+        /* east */
+        glTexCoord3f(50.f, -50.f, 50.f);
+        glVertex3f(50.f, -50.f, 50.f);
+        glTexCoord3f(50.f, 50.f, 50.f);
+        glVertex3f(50.f, 50.f, 50.f);
+        glTexCoord3f(50.f, 50.f, -50.f);
+        glVertex3f(50.f, 50.f, -50.f);
+        glTexCoord3f(50.f, -50.f, -50.f);
+        glVertex3f(50.f, -50.f, -50.f);
+
+        /* west */
+        glTexCoord3f(-50.f, -50.f, 50.f);
+        glVertex3f(-50.f, -50.f, 50.f);
+        glTexCoord3f(-50.f, -50.f, -50.f);
+        glVertex3f(-50.f, -50.f, -50.f);
+        glTexCoord3f(-50.f, 50.f, -50.f);
+        glVertex3f(-50.f, 50.f, -50.f);
+        glTexCoord3f(-50.f, 50.f, 50.f);
+        glVertex3f(-50.f, 50.f, 50.f);
+
+        /* north */
+        glTexCoord3f(-50.f, -50.f, 50.f);
+        glVertex3f(-50.f, -50.f, 50.f);
+        glTexCoord3f(-50.f, 50.f, 50.f);
+        glVertex3f(-50.f, 50.f, 50.f);
+        glTexCoord3f(50.f, 50.f, 50.f);
+        glVertex3f(50.f, 50.f, 50.f);
+        glTexCoord3f(50.f, -50.f, 50.f);
+        glVertex3f(50.f, -50.f, 50.f);
+
+        /* south */
+        glTexCoord3f(-50.f, -50.f, -50.f);
+        glVertex3f(-50.f, -50.f, -50.f);
+        glTexCoord3f(50.f, -50.f, -50.f);
+        glVertex3f(50.f, -50.f, -50.f);
+        glTexCoord3f(50.f, 50.f, -50.f);
+        glVertex3f(50.f, 50.f, -50.f);
+        glTexCoord3f(-50.f, 50.f, -50.f);
+        glVertex3f(-50.f, 50.f, -50.f);
+    } glEnd();
+
+    glDisable(GL_TEXTURE_CUBE_MAP);
+}

src/rendering/twn_gl_any_rendering.c

@@ -70,6 +70,7 @@ void clear_draw_buffer(void) {
                  (1.0f / 255) * 230,
                  (1.0f / 255) * 230, 1);
 
+    /* TODO: don't clear color when skybox is applied? */
     glClear(GL_COLOR_BUFFER_BIT |
             GL_DEPTH_BUFFER_BIT |
             GL_STENCIL_BUFFER_BIT);

src/rendering/twn_rendering.c

@@ -135,6 +135,7 @@ void render(void) {
 
     clear_draw_buffer();
     render_space();
+    render_skybox(); /* after space, as to use depth buffer for early rejection */
     render_2d();
     swap_buffers();
 }

src/rendering/twn_rendering_c.h

@@ -219,4 +219,8 @@ void finally_draw_text(FontData const *font_data,
                        Color color,
                        VertexBuffer buffer);
 
+void render_skybox(void);
+
+void finally_render_skybox(char *paths_in_use);
+
 #endif

src/rendering/twn_skybox.c

@@ -0,0 +1,26 @@
+#include "twn_rendering.h"
+#include "twn_rendering_c.h"
+
+#include <SDL2/SDL.h>
+
+char *paths_in_use;
+
+void push_skybox(const char *paths) {
+    if (paths_in_use && SDL_strcmp(paths, paths_in_use) == 0)
+        return;
+
+    if (paths_in_use)
+        SDL_free(paths_in_use);
+
+    paths_in_use = SDL_strdup(paths);
+}
+
+
+void render_skybox(void) {
+    if (!paths_in_use)
+        return;
+
+    /* note: ownership of 'paths_in_use' goes there */
+    finally_render_skybox(paths_in_use);
+    paths_in_use = NULL;
+}

src/twn_textures.c

@@ -42,7 +42,7 @@ static int load_eof_callback(void *user) {
     return context->position == context->size;
 }
 
-static SDL_Surface *image_to_surface(const char *path) {
+SDL_Surface *textures_load_surface(const char *path) {
     SDL_RWops *handle = PHYSFSRWOPS_openRead(path);
     if (handle == NULL)
         goto ERR_CANNOT_OPEN_FILE;
@@ -359,7 +359,7 @@ static TextureKey textures_load(TextureCache *cache, const char *path) {
     if (i >= 0)
         return (TextureKey){ (uint16_t)i };
 
-    SDL_Surface *surface = image_to_surface(path);
+    SDL_Surface *surface = textures_load_surface(path);
     Texture new_texture = {
         .data = surface,
         .mode = infer_texture_mode(surface),

src/twn_textures_c.h

@@ -89,4 +89,8 @@ size_t textures_get_num_atlases(const TextureCache *cache);
 /* TODO: should recieve texture_cache, get_key optimization cache should be cleared some other way */
 void textures_reset_state(void);
 
+/* uncached low-level loading */
+/* warn: surface->pixels must be freed along side the surface itself */
+SDL_Surface *textures_load_surface(const char *path);
+
 #endif

src/twn_util.c

@@ -253,3 +253,20 @@ bool repeat_ftimer(float *value, float at) {
     }
     return false;
 }
+
+/* TODO: handle utf8 */
+char *expand_asterisk(const char *mask, const char *to) {
+    const char *offset = SDL_strchr(mask, '*');
+    if (!offset) {
+        CRY("Invalid path", "Asterisk should be given.");
+        return NULL;
+    }
+    size_t const mask_len = SDL_strlen(mask);
+    size_t const to_len = SDL_strlen(to);
+    char *str = SDL_malloc(mask_len + to_len); /* NULL included, replacing the original asterisk */
+    SDL_memcpy(str, mask, offset - mask);
+    SDL_memcpy(str + (offset - mask), to, to_len);
+    SDL_memcpy(str + (offset - mask) + to_len, offset + 1, mask_len - (offset - mask));
+    str[mask_len + to_len] = '\0';
+    return str;
+}

src/twn_util_c.h

@@ -0,0 +1,7 @@
+#ifndef TWN_UTIL_C_H
+#define TWN_UTIL_C_H
+
+/* note: you must free the returned string */
+char *expand_asterisk(const char *mask, const char *to);
+
+#endif