From af3957d3c300b31a0adc57b6896e66798bdfd0ef Mon Sep 17 00:00:00 2001
From: bjorn <tie.372@gmail.com>
Date: Thu, 12 Jan 2017 01:26:44 -0800
Subject: [PATCH] Perspective projection textures;

---
 src/graphics/graphics.c |  6 ++++--
 src/graphics/graphics.h |  3 ++-
 src/graphics/texture.c  | 14 +++++++++++++-
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/graphics/graphics.c b/src/graphics/graphics.c
index 78da9892..c03b151f 100644
--- a/src/graphics/graphics.c
+++ b/src/graphics/graphics.c
@@ -19,7 +19,6 @@ void lovrGraphicsInit() {
   }
   for (int i = 0; i < MAX_CANVASES; i++) {
     state.canvases[i] = malloc(sizeof(CanvasState));
-    state.canvases[i]->projection = mat4_init();
   }
   state.defaultShader = lovrShaderCreate(lovrDefaultVertexShader, lovrDefaultFragmentShader);
   state.skyboxShader = lovrShaderCreate(lovrSkyboxVertexShader, lovrSkyboxFragmentShader);
@@ -42,7 +41,6 @@ void lovrGraphicsDestroy() {
     mat4_deinit(state.transforms[i]);
   }
   for (int i = 0; i < MAX_CANVASES; i++) {
-    mat4_deinit(state.canvases[i]->projection);
     free(state.canvases[i]);
   }
   lovrRelease(&state.defaultShader->ref);
@@ -196,6 +194,10 @@ void lovrGraphicsBindTexture(Texture* texture) {
   lovrTextureBind(texture);
 }
 
+mat4 lovrGraphicsGetProjection() {
+  return state.canvases[state.canvas]->projection;
+}
+
 void lovrGraphicsSetProjection(float near, float far, float fov) {
   int width, height;
   glfwGetWindowSize(window, &width, &height);
diff --git a/src/graphics/graphics.h b/src/graphics/graphics.h
index b5d59f8b..fe3404a4 100644
--- a/src/graphics/graphics.h
+++ b/src/graphics/graphics.h
@@ -40,7 +40,7 @@ typedef struct {
 
 typedef struct CanvasState {
   int framebuffer;
-  mat4 projection;
+  float projection[16];
   int viewport[4];
 } CanvasState;
 
@@ -94,6 +94,7 @@ void lovrGraphicsSetScissor(int x, int y, int width, int height);
 Shader* lovrGraphicsGetShader();
 void lovrGraphicsSetShader(Shader* shader);
 void lovrGraphicsBindTexture(Texture* texture);
+mat4 lovrGraphicsGetProjection(); 
 void lovrGraphicsSetProjection(float near, float far, float fov);
 void lovrGraphicsSetProjectionRaw(mat4 projection);
 float lovrGraphicsGetLineWidth();
diff --git a/src/graphics/texture.c b/src/graphics/texture.c
index 61dd4061..1edb8f25 100644
--- a/src/graphics/texture.c
+++ b/src/graphics/texture.c
@@ -1,6 +1,7 @@
 #include "graphics/texture.h"
 #include "graphics/graphics.h"
 #include "util.h"
+#include <math.h>
 #include <stdlib.h>
 
 Texture* lovrTextureCreate(TextureData* textureData) {
@@ -79,7 +80,18 @@ void lovrTextureBindFramebuffer(Texture* texture) {
     mat4_setOrthographic(projection, 0, w, 0, h, -1, 1);
     lovrGraphicsSetProjectionRaw(projection);
   } else if (texture->projection == PROJECTION_PERSPECTIVE) {
-    // lovrGraphicsSetProjection(); // TODO perspective
+    mat4 projection = lovrGraphicsGetProjection();
+    float b = projection[5];
+    float c = projection[10];
+    float d = projection[14];
+    float aspect = (float) w / h;
+    float k = (c - 1.f) / (c + 1.f);
+    float near = (d * (1.f - k)) / (2.f * k);
+    float far = k * near;
+    float fov = 2.f * atan(1.f / b);
+    float newProjection[16];
+    mat4_setPerspective(newProjection, near, far, fov, aspect);
+    lovrGraphicsSetProjectionRaw(newProjection);
   }
 }