first draft at blurring

src/renderer/prerendered_texture.cpp

@@ -0,0 +1,80 @@
+#include <llmr/renderer/prerendered_texture.hpp>
+
+
+using namespace llmr;
+
+PrerenderedTexture::~PrerenderedTexture() {
+    if (texture != 0) {
+        glDeleteTextures(1, &texture);
+        texture = 0;
+    }
+
+    if (fbo != 0) {
+        glDeleteFramebuffers(1, &fbo);
+        fbo = 0;
+    }
+}
+
+
+void PrerenderedTexture::bindTexture() {
+    if (texture == 0) {
+        bindFramebuffer();
+        unbindFramebuffer();
+    }
+
+    glBindTexture(GL_TEXTURE_2D, texture);
+
+    // if (!mipmapped) {
+    //     glGenerateMipmap(GL_TEXTURE_2D);
+    //     mipmapped = true;
+    // }
+}
+
+void PrerenderedTexture::bindFramebuffer() {
+    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &previous_fbo);
+
+    if (texture == 0) {
+        glGenTextures(1, &texture);
+        glBindTexture(GL_TEXTURE_2D, texture);
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
+        glBindTexture(GL_TEXTURE_2D, 0);
+    }
+
+    if (fbo == 0) {
+        glGenFramebuffers(1, &fbo);
+        glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
+
+        GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
+        if (status != GL_FRAMEBUFFER_COMPLETE) {
+            fprintf(stderr, "Couldn't create framebuffer: ");
+            switch (status) {
+                case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT: fprintf(stderr, "incomplete attachment\n"); break;
+                case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT: fprintf(stderr, "incomplete missing attachment\n"); break;
+#ifdef GL_ES_VERSION_2_0
+                case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS: fprintf(stderr, "incomplete dimensions\n"); break;
+#else
+                case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER: fprintf(stderr, "incomplete draw buffer\n"); break;
+#endif
+                case GL_FRAMEBUFFER_UNSUPPORTED: fprintf(stderr, "unsupported\n"); break;
+                default: fprintf(stderr, "other\n"); break;
+            }
+            return;
+        }
+    } else {
+        glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+    }
+}
+
+void PrerenderedTexture::unbindFramebuffer() {
+    glBindFramebuffer(GL_FRAMEBUFFER, previous_fbo);
+
+    if (fbo != 0) {
+        glDeleteFramebuffers(1, &fbo);
+        fbo = 0;
+    }
+}