Move shaders into glsl and hlsl directories

Move `data/shaders` to `data/shaders/glsl`
Move `data/hlsl` to `data/shaders/hlsl`

Fix up shader paths in the cpp files to point to the new glsl location.

`data/shaders/hlsl/compile.py` still overwrites the glsl .spv files (for
now).

Issue: #723

data/shaders/glsl/distancefieldfonts/bitmap.frag

@@ -0,0 +1,12 @@
+#version 450
+
+layout (binding = 1) uniform sampler2D samplerColor;
+
+layout (location = 0) in vec2 inUV;
+
+layout (location = 0) out vec4 outFragColor;
+
+void main() 
+{
+	outFragColor = vec4(texture(samplerColor, inUV).a);
+}

data/shaders/glsl/distancefieldfonts/bitmap.vert

@@ -0,0 +1,18 @@
+#version 450
+
+layout (location = 0) in vec3 inPos;
+layout (location = 1) in vec2 inUV;
+
+layout (binding = 0) uniform UBO 
+{
+	mat4 projection;
+	mat4 model;
+} ubo;
+
+layout (location = 0) out vec2 outUV;
+
+void main() 
+{
+	outUV = inUV;
+	gl_Position = ubo.projection * ubo.model * vec4(inPos.xyz, 1.0);
+}

data/shaders/glsl/distancefieldfonts/generate-spirv.bat

@@ -0,0 +1,5 @@
+glslangvalidator -V sdf.vert -o sdf.vert.spv
+glslangvalidator -V sdf.frag -o sdf.frag.spv
+glslangvalidator -V bitmap.vert -o bitmap.vert.spv
+glslangvalidator -V bitmap.frag -o bitmap.frag.spv
+

data/shaders/glsl/distancefieldfonts/sdf.frag

@@ -0,0 +1,32 @@
+#version 450
+
+layout (binding = 1) uniform sampler2D samplerColor;
+
+layout (binding = 2) uniform UBO 
+{
+	vec4 outlineColor;
+	float outlineWidth;
+	float outline;
+} ubo;
+
+layout (location = 0) in vec2 inUV;
+
+layout (location = 0) out vec4 outFragColor;
+
+void main() 
+{
+    float distance = texture(samplerColor, inUV).a;
+    float smoothWidth = fwidth(distance);	
+    float alpha = smoothstep(0.5 - smoothWidth, 0.5 + smoothWidth, distance);
+	vec3 rgb = vec3(alpha);
+									 
+	if (ubo.outline > 0.0) 
+	{
+		float w = 1.0 - ubo.outlineWidth;
+		alpha = smoothstep(w - smoothWidth, w + smoothWidth, distance);
+        rgb += mix(vec3(alpha), ubo.outlineColor.rgb, alpha);
+    }									 
+									 
+    outFragColor = vec4(rgb, alpha);	
+	
+}

data/shaders/glsl/distancefieldfonts/sdf.vert

@@ -0,0 +1,18 @@
+#version 450
+
+layout (location = 0) in vec3 inPos;
+layout (location = 1) in vec2 inUV;
+
+layout (binding = 0) uniform UBO 
+{
+	mat4 projection;
+	mat4 model;
+} ubo;
+
+layout (location = 0) out vec2 outUV;
+
+void main() 
+{
+	outUV = inUV;
+	gl_Position = ubo.projection * ubo.model * vec4(inPos.xyz, 1.0);
+}