Allow custom values when clearing color, depth, and stencil buffers;

src/api/graphics.c

@@ -290,10 +290,44 @@ int l_lovrGraphicsReset(lua_State* L) {
 }
 
 int l_lovrGraphicsClear(lua_State* L) {
-  bool color = lua_gettop(L) < 1 || lua_toboolean(L, 1);
-  bool depth = lua_gettop(L) < 2 || lua_toboolean(L, 2);
-  bool stencil = lua_gettop(L) < 3 || lua_toboolean(L, 3);
-  lovrGraphicsClear(color, depth, stencil);
+  int index = 1;
+  int top = lua_gettop(L);
+
+  bool clearColor = true;
+  bool clearDepth = true;
+  bool clearStencil = true;
+  Color color = lovrGraphicsGetBackgroundColor();
+  float depth = 1.0;
+  int stencil = 0;
+
+  if (top >= index) {
+    if (lua_type(L, index) == LUA_TNUMBER) {
+      color.r = luaL_checknumber(L, index++);
+      color.g = luaL_checknumber(L, index++);
+      color.b = luaL_checknumber(L, index++);
+      color.a = luaL_optnumber(L, index++, 1.);
+    } else {
+      clearColor = lua_toboolean(L, index++);
+    }
+  }
+
+  if (top >= index) {
+    if (lua_type(L, index) == LUA_TNUMBER) {
+      depth = luaL_checknumber(L, index++);
+    } else {
+      clearDepth = lua_toboolean(L, index++);
+    }
+  }
+
+  if (top >= index) {
+    if (lua_type(L, index) == LUA_TNUMBER) {
+      stencil = luaL_checkinteger(L, index++);
+    } else {
+      clearStencil = lua_toboolean(L, index++);
+    }
+  }
+
+  lovrGraphicsClear(clearColor, clearDepth, clearStencil, color, depth, stencil);
   return 0;
 }
 
@@ -787,7 +821,8 @@ int l_lovrGraphicsStencil(lua_State* L) {
   int replaceValue = luaL_optinteger(L, 3, 1);
   bool keepValues = lua_toboolean(L, 4);
   if (!keepValues) {
-    lovrGraphicsClear(false, false, true);
+    int clearTo = lua_isnumber(L, 4) ? lua_tonumber(L, 4) : 0;
+    lovrGraphicsClear(false, false, true, (Color) { 0, 0, 0, 0 }, 0, clearTo);
   }
   lua_settop(L, 1);
   lovrGraphicsStencil(action, replaceValue, stencilCallback, L);

src/graphics/canvas.c

@@ -78,7 +78,7 @@ Canvas* lovrCanvasCreate(int width, int height, TextureFormat format, CanvasType
   }
 
   lovrAssert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE, "Error creating Canvas");
-  lovrGraphicsClear(true, true, true);
+  lovrGraphicsClear(true, true, true, (Color) { 0, 0, 0, 0 }, 1., 0);
   glBindFramebuffer(GL_FRAMEBUFFER, 0);
 
   return canvas;

src/graphics/graphics.c

@@ -81,9 +81,19 @@ void lovrGraphicsReset() {
   lovrGraphicsOrigin();
 }
 
-void lovrGraphicsClear(bool color, bool depth, bool stencil) {
-  if (!color && !depth && !stencil) return;
-  glClear((color ? GL_COLOR_BUFFER_BIT : 0) | (depth ? GL_DEPTH_BUFFER_BIT : 0) | (stencil ? GL_STENCIL_BUFFER_BIT : 0));
+void lovrGraphicsClear(bool clearColor, bool clearDepth, bool clearStencil, Color color, float depth, int stencil) {
+  if (clearColor) {
+    float c[4] = { color.r, color.g, color.b, color.a };
+    glClearBufferfv(GL_COLOR, 0, c);
+  }
+
+  if (clearDepth) {
+    glClearBufferfv(GL_DEPTH, 0, &depth);
+  }
+
+  if (clearStencil) {
+    glClearBufferiv(GL_STENCIL, 0, &stencil);
+  }
 }
 
 void lovrGraphicsPresent() {

src/graphics/graphics.h

@@ -139,7 +139,7 @@ typedef struct {
 void lovrGraphicsInit();
 void lovrGraphicsDestroy();
 void lovrGraphicsReset();
-void lovrGraphicsClear(bool color, bool depth, bool stencil);
+void lovrGraphicsClear(bool clearColor, bool clearDepth, bool clearStencil, Color color, float depth, int stencil);
 void lovrGraphicsPresent();
 void lovrGraphicsPrepare(Material* material, float* pose);
 void lovrGraphicsCreateWindow(int w, int h, bool fullscreen, int msaa, const char* title, const char* icon);

src/headset/fake.c

@@ -348,7 +348,7 @@ static void fakeRenderTo(headsetRenderCallback callback, void* userdata) {
   lovrGraphicsMatrixTransform(MATRIX_VIEW, inv);
 
   lovrGraphicsSetProjection(state.projection);
-  lovrGraphicsClear(true, true, true);
+  lovrGraphicsClear(true, true, true, lovrGraphicsGetBackgroundColor(), 1., 0);
   callback(EYE_LEFT, userdata);
   lovrGraphicsPop();
 }

src/headset/openvr.c

@@ -756,7 +756,7 @@ static void openvrRenderTo(headsetRenderCallback callback, void* userdata) {
     lovrGraphicsPush();
     lovrGraphicsMatrixTransform(MATRIX_VIEW, transform);
     lovrGraphicsSetProjection(projection);
-    lovrGraphicsClear(true, true, false);
+    lovrGraphicsClear(true, true, false, (Color) { 0, 0, 0, 0 }, 1., 0);
     callback(eye, userdata);
     lovrGraphicsPop();
     lovrCanvasResolveMSAA(state.canvas);