Start matrix stack operations;

src/graphics/graphics.c

@@ -12,12 +12,13 @@
 
 typedef struct {
   Shader* activeShader;
+  vec_mat4_t transforms;
 } GraphicsState;
 
-static GraphicsState graphicsState;
+GraphicsState graphicsState;
 
 void lovrGraphicsInit() {
-  //
+  vec_init(&graphicsState.transforms);
 }
 
 void lovrGraphicsClear(int color, int depth) {
@@ -61,6 +62,20 @@ void lovrGraphicsSetShader(Shader* shader) {
   glUseProgram(shader->id);
 }
 
+int lovrGraphicsPush() {
+  vec_mat4_t* transforms = &graphicsState.transforms;
+  if (transforms->length > 64) { return 1; }
+  vec_push(transforms, transforms->length > 0 ? mat4_copy(vec_last(transforms)) : mat4_init());
+  return 0;
+}
+
+int lovrGraphicsPop() {
+  vec_mat4_t* transforms = &graphicsState.transforms;
+  if (transforms->length == 0) { return 1; }
+  mat4_deinit(vec_pop(transforms));
+  return 0;
+}
+
 Buffer* lovrGraphicsNewBuffer(int size, BufferDrawMode drawMode, BufferUsage usage) {
   Buffer* buffer = malloc(sizeof(Buffer));
 

src/graphics/graphics.h

@@ -1,6 +1,12 @@
 #include "buffer.h"
 #include "model.h"
 #include "shader.h"
+#include "../matrix.h"
+
+#ifndef LOVR_GRAPHICS_TYPES
+#define LOVR_GRAPHICS_TYPES
+typedef vec_t(mat4) vec_mat4_t;
+#endif
 
 void lovrGraphicsInit();
 void lovrGraphicsClear(int color, int depth);
@@ -9,6 +15,8 @@ void lovrGraphicsGetClearColor(float* r, float* g, float* b, float* a);
 void lovrGraphicsSetClearColor(float r, float g, float b, float a);
 Shader* lovrGraphicsGetShader();
 void lovrGraphicsSetShader(Shader* shader);
+int lovrGraphicsPush();
+int lovrGraphicsPop();
 Buffer* lovrGraphicsNewBuffer(int size, BufferDrawMode drawMode, BufferUsage usage);
 Model* lovrGraphicsNewModel(const char* path);
 Shader* lovrGraphicsNewShader(const char* vertexSource, const char* fragmentSource);

src/lovr/graphics.c

@@ -11,6 +11,8 @@ const luaL_Reg lovrGraphics[] = {
   { "getClearColor", l_lovrGraphicsGetClearColor },
   { "setClearColor", l_lovrGraphicsSetClearColor },
   { "setShader", l_lovrGraphicsSetShader },
+  { "push", l_lovrGraphicsPush },
+  { "pop", l_lovrGraphicsPop },
   { "newModel", l_lovrGraphicsNewModel },
   { "newBuffer", l_lovrGraphicsNewBuffer },
   { "newShader", l_lovrGraphicsNewShader },
@@ -84,6 +86,22 @@ int l_lovrGraphicsSetShader(lua_State* L) {
   return 0;
 }
 
+int l_lovrGraphicsPush(lua_State* L) {
+  if (lovrGraphicsPush()) {
+    return luaL_error(L, "Unbalanced matrix stack (more pushes than pops?)");
+  }
+
+  return 0;
+}
+
+int l_lovrGraphicsPop(lua_State* L) {
+  if (lovrGraphicsPop()) {
+    return luaL_error(L, "Unbalanced matrix stack (more pops than pushes?)");
+  }
+
+  return 0;
+}
+
 int l_lovrGraphicsNewBuffer(lua_State* L) {
   const char* userDrawMode = luaL_optstring(L, 2, "fan");
   BufferDrawMode* drawMode = (BufferDrawMode*) map_get(&BufferDrawModes, userDrawMode);

src/lovr/graphics.h

@@ -14,6 +14,8 @@ int l_lovrGraphicsGetClearColor(lua_State* L);
 int l_lovrGraphicsSetClearColor(lua_State* L);
 int l_lovrGraphicsGetShader(lua_State* L);
 int l_lovrGraphicsSetShader(lua_State* L);
+int l_lovrGraphicsPush(lua_State* L);
+int l_lovrGraphicsPop(lua_State* L);
 int l_lovrGraphicsNewBuffer(lua_State* L);
 int l_lovrGraphicsNewModel(lua_State* L);
 int l_lovrGraphicsNewShader(lua_State* L);

src/matrix.c

@@ -10,8 +10,8 @@
 */
 
 mat4 mat4_init() {
-  mat4 matrix = calloc(16, sizeof(float));
-  return matrix;
+  mat4 matrix = malloc(16 * sizeof(float));
+  return mat4_setIdentity(matrix);
 }
 
 mat4 mat4_copy(mat4 source) {