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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 | #region File Description//-----------------------------------------------------------------------------// EffectHelpers.cs//// Microsoft XNA Community Game Platform// Copyright (C) Microsoft Corporation. All rights reserved.//-----------------------------------------------------------------------------#endregion#region Using Statementsusing System;#endregionnamespace Microsoft.Xna.Framework.Graphics{ /// <summary> /// Track which effect parameters need to be recomputed during the next OnApply. /// </summary> [Flags] internal enum EffectDirtyFlags { WorldViewProj = 1, World = 2, EyePosition = 4, MaterialColor = 8, Fog = 16, FogEnable = 32, AlphaTest = 64, ShaderIndex = 128, All = -1 } /// <summary> /// Helper code shared between the various built-in effects. /// </summary> internal static class EffectHelpers { /// <summary> /// Sets up the standard key/fill/back lighting rig. /// </summary> internal static Vector3 EnableDefaultLighting(DirectionalLight light0, DirectionalLight light1, DirectionalLight light2) { // Key light. light0.Direction = new Vector3(-0.5265408f, -0.5735765f, -0.6275069f); light0.DiffuseColor = new Vector3(1, 0.9607844f, 0.8078432f); light0.SpecularColor = new Vector3(1, 0.9607844f, 0.8078432f); light0.Enabled = true; // Fill light. light1.Direction = new Vector3(0.7198464f, 0.3420201f, 0.6040227f); light1.DiffuseColor = new Vector3(0.9647059f, 0.7607844f, 0.4078432f); light1.SpecularColor = Vector3.Zero; light1.Enabled = true; // Back light. light2.Direction = new Vector3(0.4545195f, -0.7660444f, 0.4545195f); light2.DiffuseColor = new Vector3(0.3231373f, 0.3607844f, 0.3937255f); light2.SpecularColor = new Vector3(0.3231373f, 0.3607844f, 0.3937255f); light2.Enabled = true; // Ambient light. return new Vector3(0.05333332f, 0.09882354f, 0.1819608f); } /// <summary> /// Lazily recomputes the world+view+projection matrix and /// fog vector based on the current effect parameter settings. /// </summary> internal static EffectDirtyFlags SetWorldViewProjAndFog(EffectDirtyFlags dirtyFlags, ref Matrix world, ref Matrix view, ref Matrix projection, ref Matrix worldView, bool fogEnabled, float fogStart, float fogEnd, EffectParameter worldViewProjParam, EffectParameter fogVectorParam) { // Recompute the world+view+projection matrix? if ((dirtyFlags & EffectDirtyFlags.WorldViewProj) != 0) { Matrix worldViewProj; Matrix.Multiply(ref world, ref view, out worldView); Matrix.Multiply(ref worldView, ref projection, out worldViewProj); worldViewProjParam.SetValue(worldViewProj); dirtyFlags &= ~EffectDirtyFlags.WorldViewProj; } if (fogEnabled) { // Recompute the fog vector? if ((dirtyFlags & (EffectDirtyFlags.Fog | EffectDirtyFlags.FogEnable)) != 0) { SetFogVector(ref worldView, fogStart, fogEnd, fogVectorParam); dirtyFlags &= ~(EffectDirtyFlags.Fog | EffectDirtyFlags.FogEnable); } } else { // When fog is disabled, make sure the fog vector is reset to zero. if ((dirtyFlags & EffectDirtyFlags.FogEnable) != 0) { fogVectorParam.SetValue(Vector4.Zero); dirtyFlags &= ~EffectDirtyFlags.FogEnable; } } return dirtyFlags; } /// <summary> /// Sets a vector which can be dotted with the object space vertex position to compute fog amount. /// </summary> static void SetFogVector(ref Matrix worldView, float fogStart, float fogEnd, EffectParameter fogVectorParam) { if (fogStart == fogEnd) { // Degenerate case: force everything to 100% fogged if start and end are the same. fogVectorParam.SetValue(new Vector4(0, 0, 0, 1)); } else { // We want to transform vertex positions into view space, take the resulting // Z value, then scale and offset according to the fog start/end distances. // Because we only care about the Z component, the shader can do all this // with a single dot product, using only the Z row of the world+view matrix. float scale = 1f / (fogStart - fogEnd); Vector4 fogVector = new Vector4(); fogVector.X = worldView.M13 * scale; fogVector.Y = worldView.M23 * scale; fogVector.Z = worldView.M33 * scale; fogVector.W = (worldView.M43 + fogStart) * scale; fogVectorParam.SetValue(fogVector); } } /// <summary> /// Lazily recomputes the world inverse transpose matrix and /// eye position based on the current effect parameter settings. /// </summary> internal static EffectDirtyFlags SetLightingMatrices(EffectDirtyFlags dirtyFlags, ref Matrix world, ref Matrix view, EffectParameter worldParam, EffectParameter worldInverseTransposeParam, EffectParameter eyePositionParam) { // Set the world and world inverse transpose matrices. if ((dirtyFlags & EffectDirtyFlags.World) != 0) { Matrix worldTranspose; Matrix worldInverseTranspose; Matrix.Invert(ref world, out worldTranspose); Matrix.Transpose(ref worldTranspose, out worldInverseTranspose); worldParam.SetValue(world); worldInverseTransposeParam.SetValue(worldInverseTranspose); dirtyFlags &= ~EffectDirtyFlags.World; } // Set the eye position. if ((dirtyFlags & EffectDirtyFlags.EyePosition) != 0) { Matrix viewInverse; Matrix.Invert(ref view, out viewInverse); eyePositionParam.SetValue(viewInverse.Translation); dirtyFlags &= ~EffectDirtyFlags.EyePosition; } return dirtyFlags; } /// <summary> /// Sets the diffuse/emissive/alpha material color parameters. /// </summary> internal static void SetMaterialColor(bool lightingEnabled, float alpha, ref Vector3 diffuseColor, ref Vector3 emissiveColor, ref Vector3 ambientLightColor, EffectParameter diffuseColorParam, EffectParameter emissiveColorParam) { // Desired lighting model: // // ((AmbientLightColor + sum(diffuse directional light)) * DiffuseColor) + EmissiveColor // // When lighting is disabled, ambient and directional lights are ignored, leaving: // // DiffuseColor + EmissiveColor // // For the lighting disabled case, we can save one shader instruction by precomputing // diffuse+emissive on the CPU, after which the shader can use DiffuseColor directly, // ignoring its emissive parameter. // // When lighting is enabled, we can merge the ambient and emissive settings. If we // set our emissive parameter to emissive+(ambient*diffuse), the shader no longer // needs to bother adding the ambient contribution, simplifying its computation to: // // (sum(diffuse directional light) * DiffuseColor) + EmissiveColor // // For futher optimization goodness, we merge material alpha with the diffuse // color parameter, and premultiply all color values by this alpha. if (lightingEnabled) { Vector4 diffuse = new Vector4(); Vector3 emissive = new Vector3(); diffuse.X = diffuseColor.X * alpha; diffuse.Y = diffuseColor.Y * alpha; diffuse.Z = diffuseColor.Z * alpha; diffuse.W = alpha; emissive.X = (emissiveColor.X + ambientLightColor.X * diffuseColor.X) * alpha; emissive.Y = (emissiveColor.Y + ambientLightColor.Y * diffuseColor.Y) * alpha; emissive.Z = (emissiveColor.Z + ambientLightColor.Z * diffuseColor.Z) * alpha; diffuseColorParam.SetValue(diffuse); emissiveColorParam.SetValue(emissive); } else { Vector4 diffuse = new Vector4(); diffuse.X = (diffuseColor.X + emissiveColor.X) * alpha; diffuse.Y = (diffuseColor.Y + emissiveColor.Y) * alpha; diffuse.Z = (diffuseColor.Z + emissiveColor.Z) * alpha; diffuse.W = alpha; diffuseColorParam.SetValue(diffuse); } } }} |
