[2810] | 1 | //======================================================================================= |
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| 2 | string description = "Screenspace Ambient Occlusion"; |
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| 3 | //======================================================================================= |
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| 4 | |
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| 5 | |
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| 6 | //======================================================================================= |
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| 7 | |
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| 8 | |
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| 9 | #define SAMPLES 24 |
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| 10 | |
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| 11 | static const float2 samples[SAMPLES] = |
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| 12 | { |
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| 13 | {-0.326212f, -0.405805f}, |
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| 14 | {-0.840144f, -0.07358f}, |
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| 15 | {-0.695914f, 0.457137f}, |
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| 16 | {-0.203345f, 0.620716}, |
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| 17 | {0.96234f, -0.194983f}, |
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| 18 | {0.473434f, -0.480026f}, |
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| 19 | {0.519456, 0.767022f}, |
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| 20 | {0.185461f, -0.893124f}, |
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| 21 | {0.507431f, 0.064425f}, |
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| 22 | {0.89642f, 0.412458f}, |
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| 23 | {-0.32194f, -0.932615f}, |
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| 24 | {-0.791559f, -0.597705f}, |
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| 25 | {0.326212f, 0.405805f}, |
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| 26 | {0.840144f, 0.07358f}, |
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| 27 | {0.695914f, -0.457137f}, |
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| 28 | {0.203345f, -0.620716}, |
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| 29 | {-0.96234f, 0.194983f}, |
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| 30 | {-0.473434f, 0.480026f}, |
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| 31 | {-0.519456, -0.767022f}, |
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| 32 | {-0.185461f, 0.893124f}, |
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| 33 | {-0.507431f, -0.064425f}, |
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| 34 | {-0.89642f, -0.412458f}, |
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| 35 | {0.32194f, 0.932615f}, |
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| 36 | {0.791559f, 0.597705f} |
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| 37 | }; |
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| 38 | |
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| 39 | |
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| 40 | //======================================================================================= |
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| 41 | |
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| 42 | |
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| 43 | float4x4 WorldViewProj : WorldViewProjection; |
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| 44 | float4x4 WorldView : WorldView; |
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| 45 | |
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| 46 | float4x4 CameraViewProjection; |
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| 47 | |
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| 48 | shared float3 WorldCenterPosition; // Center positions around this point (usually eye point). |
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| 49 | shared float WorldScale; // Scale positions to maintain precision. |
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| 50 | |
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| 51 | float AreaSize = 1.0; |
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| 52 | float SampleIntensity = 0.1; |
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| 53 | |
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| 54 | |
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| 55 | //======================================================================================= |
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| 56 | |
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| 57 | |
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| 58 | shared texture positions; |
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| 59 | shared texture diffuse; |
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| 60 | shared texture normals; |
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| 61 | |
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| 62 | sampler PositionsSampler = sampler_state |
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| 63 | { |
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| 64 | texture = <positions>; |
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| 65 | AddressU = CLAMP; |
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| 66 | AddressV = CLAMP; |
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| 67 | AddressW = CLAMP; |
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| 68 | MINFILTER = POINT; |
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| 69 | MAGFILTER = POINT; |
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| 70 | MIPFILTER = NONE; |
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| 71 | }; |
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| 72 | |
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| 73 | sampler DiffuseSampler = sampler_state |
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| 74 | { |
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| 75 | texture = <diffuse>; |
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| 76 | AddressU = CLAMP; |
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| 77 | AddressV = CLAMP; |
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| 78 | AddressW = CLAMP; |
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| 79 | MINFILTER = POINT; |
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| 80 | MAGFILTER = POINT; |
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| 81 | MIPFILTER = NONE; |
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| 82 | }; |
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| 83 | |
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| 84 | sampler NormalsSampler = sampler_state |
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| 85 | { |
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| 86 | texture = <normals>; |
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| 87 | AddressU = CLAMP; |
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| 88 | AddressV = CLAMP; |
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| 89 | AddressW = CLAMP; |
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| 90 | MINFILTER = POINT; |
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| 91 | MAGFILTER = POINT; |
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| 92 | MIPFILTER = NONE; |
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| 93 | }; |
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| 94 | |
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| 95 | |
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| 96 | //======================================================================================= |
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| 97 | |
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| 98 | |
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| 99 | struct VertexInput { |
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| 100 | float4 position : POSITION; |
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| 101 | float2 texcoord : TEXCOORD0; |
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| 102 | }; |
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| 103 | |
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| 104 | struct VertexOutput { |
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| 105 | float4 position : POSITION; |
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| 106 | float2 texcoord : TEXCOORD0; |
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| 107 | }; |
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| 108 | |
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| 109 | struct PixelOutput { |
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| 110 | float4 color : COLOR0; |
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| 111 | }; |
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| 112 | |
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| 113 | |
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| 114 | //======================================================================================= |
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| 115 | |
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| 116 | |
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| 117 | VertexOutput vs_render(VertexInput IN) |
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| 118 | { |
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| 119 | VertexOutput OUT; |
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| 120 | |
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| 121 | OUT.position = float4(IN.position.xyz, 1.0); |
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| 122 | OUT.texcoord = IN.texcoord; |
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| 123 | |
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| 124 | return OUT; |
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| 125 | } |
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| 126 | |
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| 127 | |
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| 128 | //======================================================================================= |
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| 129 | |
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| 130 | |
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| 131 | PixelOutput ps_render(VertexOutput IN) |
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| 132 | { |
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| 133 | PixelOutput OUT; |
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| 134 | |
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| 135 | float4 positions = tex2D(PositionsSampler, IN.texcoord); |
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| 136 | float4 normals = tex2D(NormalsSampler, IN.texcoord); |
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| 137 | |
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| 138 | float3 current_position = positions.xyz; |
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| 139 | float3 current_normal = normals.xyz * 2.0 - 1.0; |
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| 140 | |
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| 141 | // Get postprojection Z value to adjust AO area size. |
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| 142 | float3 worldposition = (positions.xyz / WorldScale) + WorldCenterPosition; |
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| 143 | float4 projected_position = mul(float4(worldposition.xyz, 1.0), CameraViewProjection); |
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| 144 | projected_position.xyz /= projected_position.w; |
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| 145 | |
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| 146 | |
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| 147 | // Check in a circular area around the current position. |
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| 148 | // Shoot vectors to the positions there, and check the angle to these positions. |
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| 149 | // Summing up these angles gives an estimation of the occlusion at the current position. |
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| 150 | |
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| 151 | float total_ao = 0.0; |
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| 152 | |
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| 153 | for (float sample = 0.0; sample < SAMPLES; sample++) |
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| 154 | { |
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| 155 | float2 offset = samples[sample]; |
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| 156 | float2 texcoord = IN.texcoord + offset * AreaSize * (1.0 - projected_position.z); |
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| 157 | |
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| 158 | float3 sample_position = tex2D(PositionsSampler, texcoord).xyz; |
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| 159 | |
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| 160 | float3 vector_to_sample = sample_position - current_position; |
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| 161 | float length_to_sample = length(vector_to_sample); |
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| 162 | float3 direction_to_sample = vector_to_sample / length_to_sample; |
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| 163 | length_to_sample /= WorldScale; |
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| 164 | |
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| 165 | // Angle between current normal and direction to sample controls AO intensity. |
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| 166 | float angle = dot(direction_to_sample, current_normal); |
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| 167 | angle = max(angle, 0.0); |
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| 168 | |
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| 169 | // Distance between current position and sample position controls AO intensity. |
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| 170 | float distance_intensity = 1.0 - length_to_sample * 2.0; |
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| 171 | distance_intensity = max(distance_intensity, 0.0); |
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| 172 | |
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| 173 | total_ao += angle * SampleIntensity * distance_intensity; |
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| 174 | } |
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| 175 | |
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| 176 | |
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| 177 | OUT.color = float4(0.0, 0.0, 0.0, total_ao); |
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| 178 | |
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| 179 | return OUT; |
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| 180 | } |
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| 181 | |
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| 182 | |
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| 183 | //======================================================================================= |
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| 184 | |
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| 185 | |
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| 186 | technique render |
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| 187 | { |
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| 188 | pass p0 |
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| 189 | { |
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| 190 | VertexShader = compile vs_3_0 vs_render(); |
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| 191 | PixelShader = compile ps_3_0 ps_render(); |
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| 192 | } |
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| 193 | } |
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