#version 100
precision mediump int;
precision mediump float;

uniform mat4 world;
uniform mat4 worldIT;
uniform mat4 worldViewProj;
uniform mat4 texViewProj;
uniform vec4 lightPosition;
uniform vec4 lightColour;
uniform vec4 shadowDepthRange;

attribute vec4 position;
attribute vec3 normal;
attribute vec4 ambient;

varying vec4 shadowUV;
varying vec4 vColor;
varying vec4 oColour;

void main()
{
	gl_Position = position * worldViewProj;
	oColour = ambient;
	vec4 worldPos = world * position;
	vec3 worldNorm = (worldIT * vec4(normal, 1.0)).xyz;

	// Calculate lighting (simple vertex lighting)
	vec3 lightDir = normalize(lightPosition.xyz - (worldPos.xyz * lightPosition.w));

	vColor = lightColour * max(dot(lightDir, worldNorm), 0.0);

	// Calculate shadow map coords
	shadowUV = texViewProj * worldPos;
#if LINEAR_RANGE
	// Adjust by fixed depth bias, rescale into range
	shadowUV.z = (shadowUV.z - shadowDepthRange.x) * shadowDepthRange.w;
	shadowUV.xy = shadowUV.xy / shadowUV.w;
#else
	shadowUV = shadowUV / shadowUV.w;
#endif
}