Add normal DefaultShader;

It's a pretty normal shader.

etc/shaders.h

@@ -1,5 +1,6 @@
 #include "shaders/unlit.vert.h"
 #include "shaders/unlit.frag.h"
+#include "shaders/normal.frag.h"
 #include "shaders/font.frag.h"
 #include "shaders/cubemap.vert.h"
 #include "shaders/cubemap.frag.h"

etc/shaders/normal.frag

@@ -0,0 +1,9 @@
+#version 460
+#extension GL_EXT_multiview : require
+#extension GL_GOOGLE_include_directive : require
+
+#include "lovr.glsl"
+
+vec4 lovrmain() {
+  return vec4(normalize(Normal) * .5 + .5, 1);
+}

src/api/l_graphics.c

@@ -54,6 +54,7 @@ StringEntry lovrCullMode[] = {
 
 StringEntry lovrDefaultShader[] = {
   [SHADER_UNLIT] = ENTRY("unlit"),
+  [SHADER_NORMAL] = ENTRY("normal"),
   [SHADER_FONT] = ENTRY("font"),
   [SHADER_CUBEMAP] = ENTRY("cubemap"),
   [SHADER_EQUIRECT] = ENTRY("equirect"),

src/modules/graphics/graphics.c

@@ -1602,6 +1602,10 @@ ShaderSource lovrGraphicsGetDefaultShaderSource(DefaultShader type, ShaderStage
       { lovr_shader_unlit_vert, sizeof(lovr_shader_unlit_vert) },
       { lovr_shader_unlit_frag, sizeof(lovr_shader_unlit_frag) }
     },
+    [SHADER_NORMAL] = {
+      { lovr_shader_unlit_vert, sizeof(lovr_shader_unlit_vert) },
+      { lovr_shader_normal_frag, sizeof(lovr_shader_normal_frag) }
+    },
     [SHADER_FONT] = {
       { lovr_shader_unlit_vert, sizeof(lovr_shader_unlit_vert) },
       { lovr_shader_font_frag, sizeof(lovr_shader_font_frag) }

src/modules/graphics/graphics.h

@@ -269,6 +269,7 @@ const SamplerInfo* lovrSamplerGetInfo(Sampler* sampler);
 
 typedef enum {
   SHADER_UNLIT,
+  SHADER_NORMAL,
   SHADER_FONT,
   SHADER_CUBEMAP,
   SHADER_EQUIRECT,