Initial attempt: use lightmap in the object shader

To apply terrain lightmap additive color (from environmental point lights / effects) to objects. For appearances, decrease how much this is applied based on the height above the terrain.

data/base/shaders/tcmask_depth_instanced.vert

@@ -35,6 +35,10 @@ VERTEX_INPUT vec4 instancePackedValues; // shaderStretch_ecmState_alphaTest_anim
 VERTEX_INPUT vec4 instanceColour;
 VERTEX_INPUT vec4 instanceTeamColour;
 
+float when_gt(float x, float y) {
+  return max(sign(x - y), 0.0);
+}
+
 void main()
 {
 	// unpack inputs
@@ -45,7 +49,10 @@ void main()
 	vec4 position = vertex;
 	if (vertex.y <= 0.0) // use vertex here directly to help shader compiler optimization
 	{
-		position.y -= stretch;
+		// NOTE: 'stretch' may be:
+		//	- if positive: building stretching
+		//	- if negative: the height above the terrain of the model intance overall
+		position.y -= (stretch * when_gt(stretch, 0.f));
 	}
 
 	// Translate every vertex according to the Model View and Projection Matrix

data/base/shaders/tcmask_instanced.frag

@@ -17,6 +17,7 @@ uniform sampler2D TextureTcmask; // tcmask
 uniform sampler2D TextureNormal; // normal map
 uniform sampler2D TextureSpecular; // specular map
 uniform sampler2DArrayShadow shadowMap; // shadow map
+uniform sampler2D lightmap_tex;
 
 uniform mat4 ViewMatrix;
 
@@ -56,6 +57,7 @@ FRAGMENT_INPUT mat4 NormalMatrix;
 FRAGMENT_INPUT vec4 colour;
 FRAGMENT_INPUT vec4 teamcolour;
 FRAGMENT_INPUT vec4 packed_ecmState_alphaTest;
+FRAGMENT_INPUT vec3 uvLightmap; // uvLightmap in .xy, heightAboveTerrain in .z
 
 // For Shadows
 FRAGMENT_INPUT vec3 fragPos;
@@ -289,6 +291,10 @@ float getShadowVisibility()
 #endif
 }
 
+vec3 blendAddEffectLighting(vec3 a, vec3 b) {
+	return min(a + b, vec3(1.0));
+}
+
 void main()
 {
 	// unpack inputs
@@ -327,6 +333,9 @@ void main()
 	vec3 L = normalize(lightDir);
 	float lambertTerm = max(dot(N, L), 0.0); //diffuse light
 	float visibility = getShadowVisibility();
+	vec4 lightmap_vec4 = texture(lightmap_tex, uvLightmap.xy, 0.f);
+	float distanceAboveTerrain = uvLightmap.z;
+	float lightmapFactor = 1.0f - (clamp(distanceAboveTerrain, 0.f, 300.f) / 300.f);
 
 	if (lambertTerm > 0.0)
 	{
@@ -350,7 +359,10 @@ void main()
 		light += diffuse * lambertTerm * diffuseMap * vanillaFactor;
 	}
 	// ambient light maxed for classic models to keep results similar to original
-	light += ambient * diffuseMap * (1.0 + (1.0 - float(specularmap)));
+	light += vec4(blendAddEffectLighting(ambient.rgb, ((lightmap_vec4.rgb * lightmapFactor) / 3.f)), ambient.a) * diffuseMap * (1.0 + (1.0 - float(specularmap)));
+
+	light.rgb *= visibility;
+	light.a = 1.0f;
 
 	vec4 fragColour;
 	if (tcmask != 0)
@@ -359,11 +371,11 @@ void main()
 		float maskAlpha = texture(TextureTcmask, texCoord, WZ_MIP_LOAD_BIAS).r;
 
 		// Apply color using grain merge with tcmask
-		fragColour = visibility * (light + (teamcolour - 0.5) * maskAlpha) * colour;
+		fragColour = (light + (teamcolour - 0.5) * maskAlpha) * colour;
 	}
 	else
 	{
-		fragColour = visibility * light * colour;
+		fragColour = light * colour;
 	}
 
 	if (ecmEffect)

data/base/shaders/tcmask_instanced.vert

@@ -13,6 +13,8 @@
 
 uniform mat4 ProjectionMatrix;
 uniform mat4 ViewMatrix;
+uniform mat4 ModelUVLightmapMatrix;
+
 uniform int hasTangents; // whether tangents were calculated for model
 uniform vec4 lightPosition;
 
@@ -45,11 +47,16 @@ VERTEX_OUTPUT mat4 NormalMatrix;
 VERTEX_OUTPUT vec4 colour;
 VERTEX_OUTPUT vec4 teamcolour;
 VERTEX_OUTPUT vec4 packed_ecmState_alphaTest;
+VERTEX_OUTPUT vec3 uvLightmap; // uvLightmap in .xy, heightAboveTerrain in .z
 
 // for Shadows
 VERTEX_OUTPUT vec3 fragPos;
 VERTEX_OUTPUT vec3 fragNormal;
 
+float when_gt(float x, float y) {
+  return max(sign(x - y), 0.0);
+}
+
 void main()
 {
 	// unpack inputs
@@ -93,13 +100,19 @@ void main()
 	vec4 position = vertex;
 	if (vertex.y <= 0.0) // use vertex here directly to help shader compiler optimization
 	{
-		position.y -= stretch;
+		// NOTE: 'stretch' may be:
+		//	- if positive: building stretching
+		//	- if negative: the height above the terrain of the model intance overall
+		position.y -= (stretch * when_gt(stretch, 0.f));
 	}
 
 	vec4 positionModelSpace = instanceModelMatrix * position;
 	fragPos = positionModelSpace.xyz;
 	fragNormal = vertexNormal;
 
+	float heightAboveTerrain = abs(clamp(sign(stretch), -1.f, 0.f)) * abs(stretch);
+	uvLightmap = vec3((ModelUVLightmapMatrix * positionModelSpace).xy, position.y + heightAboveTerrain);
+
 	// Translate every vertex according to the Model View and Projection Matrix
 	mat4 ModelViewProjectionMatrix = ProjectionMatrix * ModelViewMatrix;
 	vec4 gposition = ModelViewProjectionMatrix * position;

data/base/shaders/vk/tcmask_depth_instanced.vert

@@ -16,6 +16,10 @@ layout(location = 9) in vec4 instancePackedValues; // shaderStretch_ecmState_alp
 layout(location = 10) in vec4 instanceColour;
 layout(location = 11) in vec4 instanceTeamColour;
 
+float when_gt(float x, float y) {
+  return max(sign(x - y), 0.0);
+}
+
 void main()
 {
 	// unpack inputs
@@ -26,7 +30,10 @@ void main()
 	vec4 position = vertex;
 	if (vertex.y <= 0.0) // use vertex here directly to help shader compiler optimization
 	{
-		position.y -= stretch;
+		// NOTE: 'stretch' may be:
+		//	- if positive: building stretching
+		//	- if negative: the height above the terrain of the model intance overall
+		position.y -= (stretch * when_gt(stretch, 0.f));
 	}
 
 	// Translate every vertex according to the Model View and Projection Matrix

data/base/shaders/vk/tcmask_instanced.frag

@@ -13,6 +13,7 @@ layout(set = 2, binding = 1) uniform sampler2D TextureTcmask; // tcmask
 layout(set = 2, binding = 2) uniform sampler2D TextureNormal; // normal map
 layout(set = 2, binding = 3) uniform sampler2D TextureSpecular; // specular map
 layout(set = 2, binding = 4) uniform sampler2DArrayShadow shadowMap; // shadow map
+layout(set = 2, binding = 5) uniform sampler2D lightmap_tex;
 
 layout(location = 0) in vec4 texCoord_vertexDistance; // vec(2) texCoord, float vertexDistance, (unused float)
 layout(location = 1) in vec3 normal;
@@ -22,8 +23,9 @@ layout(location = 4) in mat4 NormalMatrix;
 layout(location = 8) in vec4 colour;
 layout(location = 9) in vec4 teamcolour;
 layout(location = 10) in vec4 packed_ecmState_alphaTest;
+layout(location = 11) in vec3 uvLightmap; // uvLightmap in .xy, heightAboveTerrain in .z
 // For Shadows
-layout(location = 11) in vec3 fragPos;
+layout(location = 12) in vec3 fragPos;
 //layout(location = 13) in vec3 fragNormal;
 
 layout(location = 0) out vec4 FragColor;
@@ -259,6 +261,10 @@ float getShadowVisibility()
 	}
 }
 
+vec3 blendAddEffectLighting(vec3 a, vec3 b) {
+	return min(a + b, vec3(1.0));
+}
+
 void main()
 {
 	// unpack inputs
@@ -297,6 +303,9 @@ void main()
 	vec3 L = normalize(lightDir);
 	float lambertTerm = max(dot(N, L), 0.0); //diffuse light
 	float visibility = getShadowVisibility();
+	vec4 lightmap_vec4 = texture(lightmap_tex, uvLightmap.xy, 0.f);
+	float distanceAboveTerrain = uvLightmap.z;
+	float lightmapFactor = 1.0f - (clamp(distanceAboveTerrain, 0.f, 300.f) / 300.f);
 
 	if (lambertTerm > 0.0)
 	{
@@ -320,7 +329,10 @@ void main()
 		light += diffuse * lambertTerm * diffuseMap * vanillaFactor;
 	}
 	// ambient light maxed for classic models to keep results similar to original
-	light += ambient * diffuseMap * (1.0 + (1.0 - float(specularmap)));
+	light += vec4(blendAddEffectLighting(ambient.rgb, ((lightmap_vec4.rgb * lightmapFactor) / 3.f)), ambient.a) * diffuseMap * (1.0 + (1.0 - float(specularmap)));
+
+	light.rgb *= visibility;
+	light.a = 1.0f;
 
 	vec4 fragColour;
 	if (tcmask != 0)
@@ -329,11 +341,11 @@ void main()
 		float maskAlpha = texture(TextureTcmask, texCoord, WZ_MIP_LOAD_BIAS).r;
 
 		// Apply color using grain merge with tcmask
-		fragColour = visibility * (light + (teamcolour - 0.5) * maskAlpha) * colour;
+		fragColour = (light + (teamcolour - 0.5) * maskAlpha) * colour;
 	}
 	else
 	{
-		fragColour = visibility * light * colour;
+		fragColour = light * colour;
 	}
 
 	if (ecmEffect)

data/base/shaders/vk/tcmask_instanced.glsl

@@ -6,6 +6,7 @@ layout(std140, set = 0, binding = 0) uniform globaluniforms
 {
 	mat4 ProjectionMatrix;
 	mat4 ViewMatrix;
+	mat4 ModelUVLightmapMatrix;
 	mat4 ShadowMapMVPMatrix[WZ_MAX_SHADOW_CASCADES];
 	vec4 lightPosition;
 	vec4 sceneColor;

data/base/shaders/vk/tcmask_instanced.vert

@@ -20,10 +20,15 @@ layout(location = 4) out mat4 NormalMatrix;
 layout(location = 8) out vec4 colour;
 layout(location = 9) out vec4 teamcolour;
 layout(location = 10) out vec4 packed_ecmState_alphaTest;
+layout(location = 11) out vec3 uvLightmap; // uvLightmap in .xy, heightAboveTerrain in .z
 // For Shadows
-layout(location = 11) out vec3 fragPos;
+layout(location = 12) out vec3 fragPos;
 //layout(location = 13) out vec3 fragNormal;
 
+float when_gt(float x, float y) {
+  return max(sign(x - y), 0.0);
+}
+
 void main()
 {
 	// unpack inputs
@@ -67,13 +72,19 @@ void main()
 	vec4 position = vertex;
 	if (vertex.y <= 0.0) // use vertex here directly to help shader compiler optimization
 	{
-		position.y -= stretch;
+		// NOTE: 'stretch' may be:
+		//	- if positive: building stretching
+		//	- if negative: the height above the terrain of the model intance overall
+		position.y -= (stretch * when_gt(stretch, 0.f));
 	}
 
 	vec4 positionModelSpace = instanceModelMatrix * position;
 	fragPos = positionModelSpace.xyz;
 //	fragNormal = vertexNormal;
 
+	float heightAboveTerrain = abs(clamp(sign(stretch), -1.f, 0.f)) * abs(stretch);
+	uvLightmap = vec3((ModelUVLightmapMatrix * positionModelSpace).xy, position.y + heightAboveTerrain);
+
 	// Translate every vertex according to the Model View and Projection Matrix
 	mat4 ModelViewProjectionMatrix = ProjectionMatrix * ModelViewMatrix;
 	vec4 gposition = ModelViewProjectionMatrix * position;

lib/ivis_opengl/gfx_api.h

@@ -730,6 +730,7 @@ namespace gfx_api
 	{
 		glm::mat4 ProjectionMatrix;
 		glm::mat4 ViewMatrix;
+		glm::mat4 ModelUVLightmapMatrix;
 		glm::mat4 ShadowMapMVPMatrix[WZ_MAX_SHADOW_CASCADES];
 		glm::vec4 sunPos;
 		glm::vec4 sceneColor;
@@ -797,7 +798,8 @@ namespace gfx_api
 	texture_description<1, sampler_type::bilinear>, // team color mask
 	texture_description<2, sampler_type::anisotropic>, // normal map
 	texture_description<3, sampler_type::anisotropic>, // specular map
-	texture_description<4, sampler_type::bilinear_border, pixel_format_target::depth_map, border_color::opaque_white>  // depth / shadow map
+	texture_description<4, sampler_type::bilinear_border, pixel_format_target::depth_map, border_color::opaque_white>,  // depth / shadow map
+	texture_description<5, sampler_type::bilinear> // lightmap
 	>, shader>;
 
 	using Draw3DShapeOpaque_Instanced = Draw3DShapeInstanced<REND_OPAQUE, SHADER_COMPONENT_INSTANCED, DEPTH_CMP_LEQ_WRT_ON>;

lib/ivis_opengl/gfx_api_gl.cpp

@@ -647,12 +647,13 @@ static const std::map<SHADER_MODE, program_data> shader_to_file_table =
 	std::make_pair(SHADER_COMPONENT_INSTANCED, program_data{ "Component program", "shaders/tcmask_instanced.vert", "shaders/tcmask_instanced.frag",
 		{
 			// per-frame global uniforms
-			"ProjectionMatrix", "ViewMatrix", "ShadowMapMVPMatrix", "lightPosition", "sceneColor", "ambient", "diffuse", "specular", "fogColor", "ShadowMapCascadeSplits", "ShadowMapSize", "fogEnd", "fogStart", "graphicsCycle", "fogEnabled",
+			"ProjectionMatrix", "ViewMatrix", "ModelUVLightmapMatrix", "ShadowMapMVPMatrix", "lightPosition", "sceneColor", "ambient", "diffuse", "specular", "fogColor", "ShadowMapCascadeSplits", "ShadowMapSize", "fogEnd", "fogStart", "graphicsCycle", "fogEnabled",
 			// per-mesh uniforms
 			"tcmask", "normalmap", "specularmap", "hasTangents"
 		},
 		{
-			{"shadowMap", 4}
+			{"shadowMap", 4},
+			{"lightmap_tex", 5}
 		} }),
 	std::make_pair(SHADER_COMPONENT_DEPTH_INSTANCED, program_data{ "Component program", "shaders/tcmask_depth_instanced.vert", "shaders/tcmask_depth_instanced.frag",
 		{
@@ -671,7 +672,7 @@ static const std::map<SHADER_MODE, program_data> shader_to_file_table =
 	std::make_pair(SHADER_NOLIGHT_INSTANCED, program_data{ "Plain program", "shaders/nolight_instanced.vert", "shaders/nolight_instanced.frag",
 		{
 			// per-frame global uniforms
-			"ProjectionMatrix", "ViewMatrix", "ShadowMapMVPMatrix", "lightPosition", "sceneColor", "ambient", "diffuse", "specular", "fogColor", "ShadowMapCascadeSplits", "ShadowMapSize", "fogEnd", "fogStart", "graphicsCycle", "fogEnabled",
+			"ProjectionMatrix", "ViewMatrix", "ModelUVLightmapMatrix", "ShadowMapMVPMatrix", "lightPosition", "sceneColor", "ambient", "diffuse", "specular", "fogColor", "ShadowMapCascadeSplits", "ShadowMapSize", "fogEnd", "fogStart", "graphicsCycle", "fogEnabled",
 			// per-mesh uniforms
 			"tcmask", "normalmap", "specularmap", "hasTangents",
 		},
@@ -1862,27 +1863,28 @@ void gl_pipeline_state_object::set_constants(const gfx_api::Draw3DShapeInstanced
 {
 	setUniforms(0, cbuf.ProjectionMatrix);
 	setUniforms(1, cbuf.ViewMatrix);
-	setUniforms(2, cbuf.ShadowMapMVPMatrix, WZ_MAX_SHADOW_CASCADES);
-	setUniforms(3, cbuf.sunPos);
-	setUniforms(4, cbuf.sceneColor);
-	setUniforms(5, cbuf.ambient);
-	setUniforms(6, cbuf.diffuse);
-	setUniforms(7, cbuf.specular);
-	setUniforms(8, cbuf.fogColour);
-	setUniforms(9, cbuf.ShadowMapCascadeSplits);
-	setUniforms(10, cbuf.ShadowMapSize);
-	setUniforms(11, cbuf.fogEnd);
-	setUniforms(12, cbuf.fogBegin);
-	setUniforms(13, cbuf.timeState);
-	setUniforms(14, cbuf.fogEnabled);
+	setUniforms(2, cbuf.ModelUVLightmapMatrix);
+	setUniforms(3, cbuf.ShadowMapMVPMatrix, WZ_MAX_SHADOW_CASCADES);
+	setUniforms(4, cbuf.sunPos);
+	setUniforms(5, cbuf.sceneColor);
+	setUniforms(6, cbuf.ambient);
+	setUniforms(7, cbuf.diffuse);
+	setUniforms(8, cbuf.specular);
+	setUniforms(9, cbuf.fogColour);
+	setUniforms(10, cbuf.ShadowMapCascadeSplits);
+	setUniforms(11, cbuf.ShadowMapSize);
+	setUniforms(12, cbuf.fogEnd);
+	setUniforms(13, cbuf.fogBegin);
+	setUniforms(14, cbuf.timeState);
+	setUniforms(15, cbuf.fogEnabled);
 }
 
 void gl_pipeline_state_object::set_constants(const gfx_api::Draw3DShapeInstancedPerMeshUniforms& cbuf)
 {
-	setUniforms(15, cbuf.tcmask);
-	setUniforms(16, cbuf.normalMap);
-	setUniforms(17, cbuf.specularMap);
-	setUniforms(18, cbuf.hasTangents);
+	setUniforms(16, cbuf.tcmask);
+	setUniforms(17, cbuf.normalMap);
+	setUniforms(18, cbuf.specularMap);
+	setUniforms(19, cbuf.hasTangents);
 }
 
 void gl_pipeline_state_object::set_constants(const gfx_api::Draw3DShapeInstancedDepthOnlyGlobalUniforms& cbuf)