opengl卡通渲染之逐顶点渲染与逐像素渲染

逐顶点渲染效果：

逐像素渲染效果

逐顶点渲染顶点shader

attribute vec3 pos;
attribute vec2 texcoord;
attribute vec3 normal;

uniform mat4 M;
uniform mat4 P;
uniform mat4 V;
uniform mat4 NM;

uniform vec3 U_LightPos;
uniform vec3 U_EyePos;
uniform vec4 U_DiffuseLightColor;
uniform vec4 U_DiffuseMaterial;
uniform vec4 U_SpecularLightColor;
uniform vec4 U_SpecularMaterial;

varying vec4 V_Color;

void main()
{
	//光线方向
	vec3 L=U_LightPos;
	L=normalize(L);
	//法向量转换到世界空间
	vec3 n=normalize(mat3(NM)*normal);

	//计算光照强度
	float intensity=max(0.0,dot(L,n));
	
	//根据不同的光照强度，计算出不同的颜色
	if (intensity > 0.95)  
        V_Color = vec4(1.0,0.5,0.5,1.0);  
    else if (intensity > 0.5)  
        V_Color = vec4(0.6,0.3,0.3,1.0);  
    else if (intensity > 0.25)  
        V_Color = vec4(0.4,0.2,0.2,1.0);  
    else  
        V_Color = vec4(0.2,0.1,0.1,1.0);  
	
	gl_Position=P*V*M*vec4(pos,1.0);
}

片元shader

uniform vec4 U_AmbientLightColor;
uniform vec4 U_AmbientMaterial;

varying vec4 V_Color;

void main()
{
	vec4 ambientColor=U_AmbientLightColor*U_AmbientMaterial;
	gl_FragColor=ambientColor+V_Color;
}

逐像素渲染顶点shader

attribute vec3 pos;
attribute vec2 texcoord;
attribute vec3 normal;

uniform mat4 M;
uniform mat4 P;
uniform mat4 V;
uniform mat4 NM;

varying vec3 V_Normal;
varying vec3 V_WorldPos;

void main()
{
	V_Normal=mat3(NM)*normal;
	vec4 worldPos=M*vec4(pos,1.0);
	V_WorldPos=worldPos.xyz;

	gl_Position=P*V*worldPos;
}

片元shader

uniform vec3 U_LightPos;
uniform vec3 U_EyePos;
uniform vec4 U_AmbientLightColor;
uniform vec4 U_AmbientMaterial;
uniform vec4 U_DiffuseLightColor;
uniform vec4 U_DiffuseMaterial;
uniform vec4 U_SpecularLightColor;
uniform vec4 U_SpecularMaterial;

varying vec3 V_Normal;
varying vec3 V_WorldPos;

void main()
{
	//计算环境光
	vec4 ambientColor=U_AmbientLightColor*U_AmbientMaterial;


	//光线方向
	vec3 L=U_LightPos;
	L=normalize(L);
	//法向量转换到世界空间
	vec3 n=normalize(V_Normal);

	//根据不同的光照强度给出不同颜色值
	float diffuseIntensity=max(0.0,dot(L,n));
	vec4 diffuseColor;
    if (diffuseIntensity > 0.95)  
        diffuseColor = vec4(1.0,0.5,0.5,1.0);  
    else if (diffuseIntensity > 0.5)  
        diffuseColor = vec4(0.6,0.3,0.3,1.0);  
    else if (diffuseIntensity > 0.25)  
        diffuseColor = vec4(0.4,0.2,0.2,1.0);  
    else  
        diffuseColor = vec4(0.2,0.1,0.1,1.0);  

	gl_FragColor=ambientColor+diffuseColor;
}