Added frame buffer support.

src/display/framebuffer.c

@@ -0,0 +1,68 @@
+/**
+ * Copyright (c) 2021 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "framebuffer.h"
+
+framebuffer_t * frameBufferCreate(int32_t w, int32_t h) {
+  framebuffer_t *fb = malloc(sizeof(framebuffer_t));
+  if(fb == NULL) return NULL;
+
+  // Create Color Attachment texture.
+  fb->texture = textureCreate(w, h, NULL);
+  if(fb->texture == NULL) {
+    free(fb);
+    return NULL;
+  }
+
+  // Create Frame Buffer
+  glGenFramebuffers(1, &fb->fboId);
+  glBindFramebuffer(GL_FRAMEBUFFER, fb->fboId);
+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
+    GL_TEXTURE_2D, fb->texture->id, 0
+  );
+
+  // Render Buffer
+  glGenRenderbuffers(1, &fb->rboId);
+  glBindRenderbuffer(GL_RENDERBUFFER, fb->rboId); 
+  glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, w, h);
+  glBindRenderbuffer(GL_RENDERBUFFER, 0);
+  glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
+    GL_RENDERBUFFER, fb->rboId
+  );
+
+  if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+    uint32_t error;
+    error = 0;
+  }
+
+  glBindFramebuffer(GL_FRAMEBUFFER, 0);
+
+  return fb;
+}
+
+void frameBufferUse(framebuffer_t *frameBuffer, bool clear) {
+  if(frameBuffer == NULL) {
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    glViewport(0, 0, RENDER_STATE.width, RENDER_STATE.height);
+  } else {
+    glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer->fboId);
+    glViewport(0, 0, frameBuffer->texture->width, frameBuffer->texture->height);
+  }
+
+  if(clear) {
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+  }
+}
+
+void frameBufferDispose(framebuffer_t *frameBuffer) {
+  glBindFramebuffer(GL_FRAMEBUFFER, 0);
+  glBindRenderbuffer(GL_RENDERBUFFER, 0);
+  glDeleteRenderbuffers(1, &frameBuffer->rboId);
+  glDeleteFramebuffers(1, &frameBuffer->fboId);
+  textureDispose(frameBuffer->texture);
+  free(frameBuffer);
+}

src/display/framebuffer.h

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) 2021 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#pragma once
+#include <dawn/dawn.h>
+#include "texture.h"
+
+/**
+ * Creates a new frame buffer that can be rendered to.
+ * 
+ * @param width Width of the frame buffer (in pixels).
+ * @param height Height of the frame buffer (in pixels).
+ * @return A renderable frame buffer.
+ */
+framebuffer_t * frameBufferCreate(int32_t width, int32_t height);
+
+/**
+ * Use a given frame buffer as the current rendering context.
+ * 
+ * @param frameBuffer Frame buffer to use, or NULL to not use any.
+ * @param clear Whether or not to clear the frame buffer prior to rendering.
+ */
+void frameBufferUse(framebuffer_t *frameBuffer, bool clear);
+
+/**
+ * Dispose/cleanup a previously created frame buffer.
+ * 
+ * @param frameBuffer Frame Buffer to clean.
+ */
+void frameBufferDispose(framebuffer_t *frameBuffer);

src/display/gui/font.h

@@ -11,7 +11,28 @@
 
 #define FONT_CHAR_START 33
 
+/**
+ * Get the division for a given character.
+ * 
+ * @param tileset Tileset to get the division from.
+ * @param character Character to get the division for.
+ * @return The division from the tileset for the character.
+ */
 tilesetdiv_t * fontGetCharacterDivision(tileset_t *tileset, char character);
+
+/**
+ * Renders a set of font characters to the sprite. Coordinates are anchored to
+ * the top left (0,0) origin.
+ * 
+ * @param batch Sprite Batch to render to.
+ * @param tileset Tileset for the font.
+ * @param string String to render.
+ * @param x Position in X space.
+ * @param y Position in Y space.
+ * @param z Position in Z space.
+ * @param charWidth Width of each character.
+ * @param charHeight Height of each character.
+ */
 void fontSpriteBatchBuffer(spritebatch_t *batch, tileset_t *tileset,
   char *string, float x, float y, float z, float charWidth, float charHeight
 );

src/display/render.c

@@ -32,5 +32,4 @@ void renderDispose() {
 void renderSetResolution(int32_t width, int32_t height) {
   RENDER_STATE.width = width;
   RENDER_STATE.height = height;
-  glViewport(0, 0, width, height);
 }

src/display/texture.c

@@ -41,6 +41,8 @@ texture_t * textureCreate(int32_t width, int32_t height, pixel_t *pixels) {
       GL_RGBA, GL_UNSIGNED_BYTE, pixels
     );
   }
+  
+  glBindTexture(GL_TEXTURE_2D, 0);
 
   return texture;
 }