exp fog

main.cpp

@@ -99,6 +99,7 @@ INT WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _
 	gpuProgram.DetectUniform("U_FogStart");
 	gpuProgram.DetectUniform("U_FogEnd");
 	gpuProgram.DetectUniform("U_FogColor");
+	gpuProgram.DetectUniform("U_FogDensity");
 
 	
 
@@ -129,6 +130,7 @@ INT WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _
 	float fogStart = 2.0f;
 	float fogEnd = 23.0f;
 	float fogColor[] = { 0.6f, 0.6f, 0.6f, 1.0f };
+	float fogDensity = 0.11;
 
 	glm::mat4 cubeModelMatrix = glm::translate<float>(-2.2f, 0.0f, -4.0f) * glm::rotate(-30.0f, 1.0f, 1.0f, 1.0f);
 	glm::mat4 cubeNormalMatrix = glm::inverseTranspose(cubeModelMatrix);
@@ -182,6 +184,7 @@ INT WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _
 		glUniform1f(gpuProgram.GetLocation("U_FogStart"), fogStart);
 		glUniform1f(gpuProgram.GetLocation("U_FogEnd"), fogEnd);
 		glUniform4fv(gpuProgram.GetLocation("U_FogColor"), 1, fogColor);
+		glUniform1f(gpuProgram.GetLocation("U_FogDensity"), fogDensity);
 
 		glUniformMatrix4fv(gpuProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(cubeModelMatrix));
 		glUniformMatrix4fv(gpuProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(cubeNormalMatrix));

res/shader/forg.fs

@@ -13,6 +13,7 @@ uniform vec4 U_SpecularMaterial;
 uniform float U_FogStart;
 uniform float U_FogEnd;
 uniform vec4 U_FogColor;
+uniform float U_FogDensity;
 
 varying vec3 V_Normal;
 varying vec3 V_WorldPos;
@@ -25,6 +26,13 @@ float calculateLinearFog(float distance){
 	return fogAlpha;
 }
 
+float calculateExpFog(float distance)
+{
+	float fogAlpha=exp(-(distance*U_FogDensity));
+	fogAlpha=clamp(fogAlpha,0.0,1.0);
+	return fogAlpha;
+}
+
 void main()
 {
 
@@ -77,6 +85,6 @@ void main()
 	vec3 VD = normalize(U_EyePos - V_WorldPos);
 	vec4 specularColor =  U_SpecularLightColor * U_SpecularMaterial * pow(max(0.0, dot(RD,VD)) ,128);
 
-	float fogAlpha = calculateLinearFog(abs(V_EyeSpacePos.z/V_EyeSpacePos.w));
+	float fogAlpha = calculateExpFog(abs(V_EyeSpacePos.z/V_EyeSpacePos.w));
 	gl_FragColor = mix(U_FogColor,ambientColor + diffuseColor + specularColor, fogAlpha);
 }