Here's the complete code for shader.

At the moment I've calculated the normals for each vertex but not using them yet.

Also, no real lighting just adding shadows, so I'm darkening pixels where a shadow is.

As I said before I've tried several bias values. The shadows just don't look right.

This is self shadows on terrain only - at the moment.

float4x4 WorldMatrix;

float4x4 ViewMatrix;

float4x4 ProjectionMatrix;

float4x4 LightViewMatrix;

float4x4 LightProjectionMatrix;

float maxHeight; //maximum height of the terrain

Texture2D heightMap;

Texture2D shadowMap;

Texture2D sandTexture;

Texture2D grassTexture;

Texture2D snowTexture;

Texture2D rockTexture;

SamplerState pointSampler;

SamplerState linearSampler;

SamplerState shadowMapSampler;

struct VS_INPUT

{

float4 Position : SV_POSITION;

float2 UV : TEXCOORD0;

};

struct VS_OUTPUT

{

float4 Position : SV_POSITION;

float4 Normal : NORMAL0;

float2 UV : TEXCOORD0;

float4 TextureWeights : TEXCOORD1; // Weights used for multitexturing

float Depth : TEXCOORD2; // Used for texture LOD

float4 LightPosition : TEXCOORD3; // Position in light space

};

struct SHADOW_VS_INPUT

{

float4 Position : SV_POSITION;

float2 UV : TEXCOORD0;

};

struct SHADOW_VS_OUTPUT

{

float4 Position : SV_POSITION;

float4 Depth : TEXTURE0;

};

//--------------------------------------------------------------------------------------

// Vertex Shader

//--------------------------------------------------------------------------------------

VS_OUTPUT VS(VS_INPUT input)

{

float height = heightMap.SampleLevel(pointSampler, input.UV, 0).r;

input.Position.y = height * maxHeight;

float4x4 worldViewProj = mul(mul(WorldMatrix, ViewMatrix), ProjectionMatrix);

float4x4 lightWorldViewProj = mul(mul(WorldMatrix, LightViewMatrix), LightProjectionMatrix);

// Height values of adjacent vertices

float y = input.Position.y;

float N = heightMap.SampleLevel(pointSampler, input.UV, 0, float2(0,-1)).r * maxHeight;

float S = heightMap.SampleLevel(pointSampler, input.UV, 0, float2(0,1)).r * maxHeight;

float W = heightMap.SampleLevel(pointSampler, input.UV, 0, float2(-1,0)).r * maxHeight;

float E = heightMap.SampleLevel(pointSampler, input.UV, 0, float2(1,0)).r * maxHeight;

float NE = heightMap.SampleLevel(pointSampler, input.UV, 0, float2(1,-1)).r * maxHeight;

float SW = heightMap.SampleLevel(pointSampler, input.UV, 0, float2(-1,1)).r * maxHeight;

// Vectors joins adjacent vertices

float3 vectorN = float3(0, N - y, 1);

float3 vectorS = float3(0, S - y, -1);

float3 vectorE = float3(1, E - y, 0);

float3 vectorW = float3(-1, W - y, 0);

float3 vectorNE = float3(1, NE - y, 1);

float3 vectorSW = float3(-1, SW - y, -1);

// Average normal for current vertex

float3 normal = normalize(cross(vectorN, vectorNE) + cross(vectorNE, vectorE) + cross(vectorE, vectorS)

+ cross(vectorS, vectorSW) + cross(vectorSW, vectorW) + cross(vectorW, vectorN));

VS_OUTPUT output = (VS_OUTPUT)0;

output.Position = mul(input.Position, worldViewProj);

output.Normal = mul(float4(normal, 1), WorldMatrix);

float4 texWeights = 0;

texWeights.x = saturate(1.0f - height * 3.0f);

texWeights.y = saturate(1.0f - abs(height - 0.4f) * 3.0f);

texWeights.z = saturate(1.0f - abs(height - 0.9f) * 3.0f);

texWeights.w = 1;

float totalWeight = texWeights.x + texWeights.y + texWeights.z;

texWeights.xyz /= totalWeight;

texWeights.w = 1;

if (normal.y > 0.81f)

{

texWeights.w = 0;

}

else if (normal.y > 0.75)

{

texWeights.w = normal.y;

}

output.TextureWeights = texWeights;

output.UV = input.UV;

output.Depth = output.Position.z/output.Position.w;

output.LightPosition = mul(input.Position, lightWorldViewProj);

//output.LightPosition /= output.LightPosition.w;

return output;

}

//--------------------------------------------------------------------------------------

// Pixel Shader

//--------------------------------------------------------------------------------------

float4 PS(VS_OUTPUT input) : SV_TARGET

{

float blendDistance = 0.99f;

float blendWidth = 0.005f;

float blendFactor = clamp((input.Depth - blendDistance) / blendWidth, 0, 1);

float4 weights = input.TextureWeights;

float scale = 4;

float4 rock = rockTexture.Sample(linearSampler, input.UV * scale);

float4 sand = sandTexture.Sample(linearSampler, input.UV * scale);

float4 grass = grassTexture.Sample(linearSampler, input.UV * scale);

float4 snow = snowTexture.Sample(linearSampler, input.UV * scale);

float4 farColour = rock * weights.w + (1 - weights.w) * (sand * weights.x + grass * weights.y + snow * weights.z);

scale = 16;

rock = rockTexture.Sample(linearSampler, input.UV * scale);

sand = sandTexture.Sample(linearSampler, input.UV * scale);

grass = grassTexture.Sample(linearSampler, input.UV * scale);

snow = snowTexture.Sample(linearSampler, input.UV * scale);

float4 nearColour = rock * weights.w + (1 - weights.w) * (sand * weights.x + grass * weights.y + snow * weights.z);

float4 colour = lerp(nearColour, farColour, blendFactor);

//--------------------------------------------------------------------------------------

// Shadows

//--------------------------------------------------------------------------------------

input.LightPosition.xyz /= input.LightPosition.w;

float2 projectedTexCoords;

projectedTexCoords[0] = input.LightPosition.x / 2.0f + 0.5f;

projectedTexCoords[1] = input.LightPosition.y / -2.0f + 0.5f;

float shadowMapDepth = shadowMap.Sample(shadowMapSampler, projectedTexCoords).r;

if (shadowMapDepth < input.LightPosition.z - 0.0007f)

{

colour *= 0.25;

}

return colour;

}

//--------------------------------------------------------------------------------------

// Shadow Vertex Shader

//--------------------------------------------------------------------------------------

SHADOW_VS_OUTPUT ShadowMapVS(SHADOW_VS_INPUT input)

{

input.Position.w = 1.0f;

// Generate terrain height from heightmap

float height = heightMap.SampleLevel(pointSampler, input.UV, 0).r;

input.Position.y = height * maxHeight;

//float4x4 lightWorldViewProj = mul(mul(WorldMatrix, LightViewMatrix), LightProjectionMatrix);

SHADOW_VS_OUTPUT output = (SHADOW_VS_OUTPUT)0;

//output.Position = mul(input.Position, lightWorldViewProj);

output.Position = mul(input.Position, WorldMatrix);

output.Position = mul(output.Position, LightViewMatrix);

output.Position = mul(output.Position, LightProjectionMatrix);

output.Depth = output.Position;

return output;

}

//--------------------------------------------------------------------------------------

// Shadow Pixel Shader

//--------------------------------------------------------------------------------------

float4 ShadowMapPS(SHADOW_VS_OUTPUT input) : SV_TARGET

{

float zValue = input.Depth.z / input.Depth.w;

return float4(zValue, zValue, zValue, 1.0f);

}

//--------------------------------------------------------------------------------------

// Techniques

//--------------------------------------------------------------------------------------

technique ShadowMap

{

pass Pass0

{

SetVertexShader(CompileShader(vs_4_0, ShadowMapVS()));

SetGeometryShader(NULL);

SetPixelShader(CompileShader(ps_4_0, ShadowMapPS()));

}

}

technique Terrain

{

pass Pass0

{

SetVertexShader(CompileShader(vs_4_0, VS()));

SetGeometryShader(NULL);

SetPixelShader(CompileShader(ps_4_0, PS()));

}

}

**Edited by antmck2013, 19 April 2013 - 08:31 AM.**