water_vertex.cg

来自「游戏编程精粹６第中关于粒子的实时流体仿真系统,对入门的游戏开发者很有帮助．」· CG 代码 · 共 44 行

float water_fresnel(float3 I, float3 N)
{
//	float R0 = 0.0204;// pow(1.0 - 1.333, 2)/pow(1+1.333, 2);
	float R0 = pow(1.0 - 1.133, 2)/pow(1+1.133, 2);
	return R0 + (1.0 - R0)*pow(1.0 + dot(I, N), 5);
}

void main(float4 position : POSITION,
		  float3 normal   : NORMAL,

		  out float4 out_position     : POSITION,
		  out float3 T : TEXCOORD3,
		  out float3 incident         : TEXCOORD0,
		  out float3 out_normal       : TEXCOORD1,
		  out float2 screen_coord     : TEXCOORD2,
		  out float reflection_factor : COLOR,

		  uniform float4x4 texMatrix     : state.matrix.texture,
		  uniform float4x4 modelViewProj : state.matrix.mvp, 
		  uniform float4x4 modelToWorld  : state.matrix.modelview)
{
	float3 eye_pos = float3(0.0, 0.0, 0.0);

	out_position = mul(modelViewProj, position);

	float3 posW = mul(modelToWorld, position).xyz;
	normal = normalize(mul((float3x3)modelToWorld, normal));

	incident = normalize(posW - eye_pos);

	reflection_factor = water_fresnel(incident, normal);//fast_fresnel(incident, normal, fresnelValues);

	incident = mul((float3x3)texMatrix, incident);
	out_normal = mul((float3x3)texMatrix, normal);
//	T = refract(incident, out_normal, 1.333);
	//incident = incident;//mul((float3x3)texMatrix, incident);
	//out_normal = normal;//mul((float3x3)texMatrix, normal);

	screen_coord = out_position.xy/out_position.w;//oPosition.xy/oPosition.w;
	screen_coord = 0.5*(screen_coord + float2(1, 1));

	//out_normal = posW.xyz;
}