Support and default to reverse-z with infinite far plane;

etc/shaders/cubemap.vert

@@ -22,5 +22,5 @@ void main() {
   vec3 ray = vec3(uv, -1.);
   mat3 inverseViewOrientation = transpose(mat3(View));
   Direction = normalize(inverseViewOrientation * (InverseProjection * vec4(ray, 1.)).xyz);
-  Position = vec4(uv, 1, 1);
+  Position = vec4(uv, 0, 1);
 }

etc/shaders/fill.vert

@@ -9,6 +9,6 @@ void main() {
   float x = -1 + float((VertexIndex & 1) << 2);
   float y = -1 + float((VertexIndex & 2) << 1);
   UV = vec2(x, y) * .5 + .5;
-  Position = vec4(x, y, 0., 1.);
+  Position = vec4(x, y, 1., 1.);
   PointSize = 1.f;
 }

src/api/l_graphics.c

@@ -459,7 +459,7 @@ static Canvas luax_checkcanvas(lua_State* L, int index) {
     .loads = { LOAD_CLEAR, LOAD_CLEAR, LOAD_CLEAR, LOAD_CLEAR },
     .depth.format = FORMAT_D32F,
     .depth.load = LOAD_CLEAR,
-    .depth.clear = 1.f,
+    .depth.clear = 0.f,
     .samples = 4
   };
 

src/api/l_math_vectors.c

@@ -1898,7 +1898,7 @@ static int l_lovrMat4Perspective(lua_State* L) {
   float fovy = luax_checkfloat(L, 2);
   float aspect = luax_checkfloat(L, 3);
   float n = luax_checkfloat(L, 4);
-  float f = luax_checkfloat(L, 5);
+  float f = luax_optfloat(L, 5, 0.);
   mat4_perspective(m, fovy, aspect, n, f);
   lua_settop(L, 1);
   return 1;
@@ -1911,7 +1911,7 @@ static int l_lovrMat4Fov(lua_State* L) {
   float up = luax_checkfloat(L, 4);
   float down = luax_checkfloat(L, 5);
   float n = luax_checkfloat(L, 6);
-  float f = luax_checkfloat(L, 7);
+  float f = luax_optfloat(L, 7, 0.);
   mat4_fov(m, left, right, up, down, n, f);
   lua_settop(L, 1);
   return 1;

src/core/maf.h

@@ -606,20 +606,25 @@ MAF mat4 mat4_orthographic(mat4 m, float left, float right, float bottom, float
   return m;
 }
 
-// Flips Y and maps z = [-n,-f] to [0,1] after dividing by w
+// Flips Y and maps z = [-n,-f] to [0,1] after dividing by w, f == 0 inverts z with infinite far
 MAF mat4 mat4_perspective(mat4 m, float fovy, float aspect, float n, float f) {
   float cotan = 1.f  / tanf(fovy * .5f);
   memset(m, 0, 16 * sizeof(float));
   m[0] = cotan / aspect;
   m[5] = -cotan;
-  m[10] = f / (n - f);
-  m[11] = -1.f;
-  m[14] = (n * f) / (n - f);
-  m[15] = 0.f;
+  if (f == 0.f) {
+    m[10] = 0.f;
+    m[11] = -1.f;
+    m[14] = n;
+  } else {
+    m[10] = f / (n - f);
+    m[11] = -1.f;
+    m[14] = (n * f) / (n - f);
+  }
   return m;
 }
 
-// Flips Y and maps z = [-n,-f] to [0,1] after dividing by w
+// Flips Y and maps z = [-n,-f] to [0,1] after dividing by w, f == 0 inverts z with infinite far
 MAF mat4 mat4_fov(mat4 m, float left, float right, float up, float down, float n, float f) {
   left = -tanf(left);
   right = tanf(right);
@@ -630,9 +635,15 @@ MAF mat4 mat4_fov(mat4 m, float left, float right, float up, float down, float n
   m[5] = 2.f / (down - up);
   m[8] = (right + left) / (right - left);
   m[9] = (down + up) / (down - up);
-  m[10] = f / (n - f);
-  m[11] = -1.f;
-  m[14] = (n * f) / (n - f);
+  if (f == 0.f) {
+    m[10] = 0.f;
+    m[11] = -1.f;
+    m[14] = n;
+  } else {
+    m[10] = f / (n - f);
+    m[11] = -1.f;
+    m[14] = (n * f) / (n - f);
+  }
   return m;
 }
 

src/modules/graphics/graphics.c

@@ -3064,7 +3064,7 @@ Pass* lovrGraphicsGetPass(PassInfo* info) {
     .depth.format = canvas->depth.texture ? canvas->depth.texture->info.format : canvas->depth.format,
     .multisample.count = canvas->samples,
     .viewCount = main->depth,
-    .depth.test = GPU_COMPARE_LEQUAL,
+    .depth.test = GPU_COMPARE_GEQUAL,
     .depth.write = true
   };
 
@@ -3094,7 +3094,7 @@ Pass* lovrGraphicsGetPass(PassInfo* info) {
   pass->cameras = tempAlloc(pass->cameraCount * sizeof(Camera));
   for (uint32_t i = 0; i < pass->cameraCount; i++) {
     mat4_identity(pass->cameras[i].view);
-    mat4_perspective(pass->cameras[i].projection, 1.f, (float) main->width / main->height, .01f, 100.f);
+    mat4_perspective(pass->cameras[i].projection, 1.f, (float) main->width / main->height, .01f, 0.f);
   }
   pass->cameraDirty = true;
 

src/modules/headset/headset_desktop.c

@@ -39,7 +39,7 @@ static void onFocus(bool focused) {
 static bool desktop_init(float supersample, float offset, uint32_t msaa, bool overlay) {
   state.offset = offset;
   state.clipNear = .01f;
-  state.clipFar = 100.f;
+  state.clipFar = 0.f;
   state.prevDisplayTime = os_get_time();
   state.nextDisplayTime = state.prevDisplayTime;
 

src/modules/headset/headset_openxr.c

@@ -783,7 +783,7 @@ static bool openxr_init(float supersample, float offset, uint32_t msaa, bool ove
   }
 
   state.clipNear = .01f;
-  state.clipFar = 100.f;
+  state.clipFar = 0.f;
   state.frameState.type = XR_TYPE_FRAME_STATE;
   return true;
 }