diff --git a/src/api.h b/src/api.h
index f987adfb..8ced41e8 100644
--- a/src/api.h
+++ b/src/api.h
@@ -121,3 +121,4 @@ int luax_pushvariant(lua_State* L, Variant* variant);
 int luax_checkuniform(lua_State* L, int index, const Uniform* uniform, void* dest, const char* debug);
 void luax_checkuniformtype(lua_State* L, int index, UniformType* baseType, int* components);
 int luax_optmipmap(lua_State* L, int index, Texture* texture);
+Texture* luax_checktexture(lua_State* L, int index);
diff --git a/src/api/graphics.c b/src/api/graphics.c
index 1b095b35..886fc2f6 100644
--- a/src/api/graphics.c
+++ b/src/api/graphics.c
@@ -829,7 +829,7 @@ int l_lovrGraphicsSphere(lua_State* L) {
 }
 
 int l_lovrGraphicsSkybox(lua_State* L) {
-  Texture* texture = luax_checktype(L, 1, Texture);
+  Texture* texture = luax_checktexture(L, 1);
   float angle = luaL_optnumber(L, 2, 0);
   float ax = luaL_optnumber(L, 3, 0);
   float ay = luaL_optnumber(L, 4, 1);
@@ -864,7 +864,7 @@ int l_lovrGraphicsStencil(lua_State* L) {
 }
 
 int l_lovrGraphicsFill(lua_State* L) {
-  Texture* texture = lua_isnoneornil(L, 1) ? NULL : luax_checktype(L, 1, Texture);
+  Texture* texture = lua_isnoneornil(L, 1) ? NULL : luax_checktexture(L, 1);
   lovrGraphicsFill(texture);
   return 0;
 }
@@ -1005,7 +1005,7 @@ int l_lovrGraphicsNewMaterial(lua_State* L) {
     lovrRelease(textureData);
     lovrRelease(texture);
   } else if (lua_isuserdata(L, index)) {
-    Texture* texture = luax_checktype(L, index, Texture);
+    Texture* texture = luax_checktexture(L, index);
     lovrMaterialSetTexture(material, TEXTURE_DIFFUSE, texture);
     index++;
   }
diff --git a/src/api/types/canvas.c b/src/api/types/canvas.c
index aa60e121..24763771 100644
--- a/src/api/types/canvas.c
+++ b/src/api/types/canvas.c
@@ -2,6 +2,16 @@
 #include "graphics/canvas.h"
 #include "graphics/graphics.h"
 
+Texture* luax_checktexture(lua_State* L, int index) {
+  Canvas* canvas = luax_totype(L, index, Canvas);
+  if (canvas) {
+    const Attachment* attachment = lovrCanvasGetAttachments(canvas, NULL);
+    return attachment->texture;
+  } else {
+    return luax_checktype(L, index, Texture);
+  }
+}
+
 static int luax_checkattachment(lua_State* L, int index, Attachment* attachment) {
   attachment->texture = luax_checktype(L, index++, Texture);
   attachment->slice = lua_type(L, index) == LUA_TNUMBER ? lua_tointeger(L, index++) - 1 : 0;
diff --git a/src/api/types/material.c b/src/api/types/material.c
index 6a39e6f6..6605320d 100644
--- a/src/api/types/material.c
+++ b/src/api/types/material.c
@@ -57,7 +57,7 @@ int l_lovrMaterialSetTexture(lua_State* L) {
     textureType = luaL_checkoption(L, index, NULL, MaterialTextures);
     index++;
   }
-  Texture* texture = lua_isnoneornil(L, index) ? NULL : luax_checktype(L, index, Texture);
+  Texture* texture = lua_isnoneornil(L, index) ? NULL : luax_checktexture(L, index);
   lovrMaterialSetTexture(material, textureType, texture);
   return 0;
 }
diff --git a/src/graphics/opengl.c b/src/graphics/opengl.c
index b318b277..90f31bb7 100644
--- a/src/graphics/opengl.c
+++ b/src/graphics/opengl.c
@@ -538,7 +538,7 @@ static void lovrGpuUseProgram(uint32_t program) {
 static void lovrGpuSetViewports(float viewports[][4], int viewportCount, int index) {
 #ifdef GL_ARB_viewport_array
     if (state.supportsSinglepass) {
-      glViewportArrayv(0, viewportCount, viewports);
+      glViewportArrayv(0, viewportCount, &viewports[0][0]);
     } else {
 #endif
       glViewport(viewports[index][0], viewports[index][1], viewports[index][2], viewports[index][3]);