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我正在研究Java + LWJGL項目。目前我正在嘗試實現方差陰影貼圖,但只有我在着色器中採樣的第一個陰影貼圖出現在正確的位置。爲什麼只有在正確的位置呈現第一個陰影?
片段着色器:
#version 330 core
in vec2 passTexCoords;
in vec4[4] shadowCoords;
//Fragment color
out vec4 out_Color;
uniform sampler2D modelTexture;
uniform sampler2D[4] shadowMaps;
#define SHADOW_BIAS 0.0005
float linstep(float low, float high, float v) {
return clamp((v-low)/(high-low), 0.0, 1.0);
}
//compare ... The depth of the fragment in shadow map sapce
float sampleVarianceShadowMap(in sampler2D shadowMap, in vec2 coords, in float compare) {
/* This is the Code that I want to use when I know what the problem was.
vec2 moments = texture(shadowMap, coords.xy).rg;
float p = step(compare, moments.x);
float variance = max(moments.y - moments.x * moments.x, 0.00002);
float d = compare - moments.x;
float pMax = linstep(0.2, 1.0, variance/(variance + d*d));
return min(max(p, pMax), 1.0);
*/
//============================================================================HERE=========================================================================HERE====================
//THE ERROR OCCURES HERE:
//This doesn't work:
float visibility = step(compare-SHADOW_BIAS, texture(shadowMap, coords.xy).r);
return visibility;
//The shadows on the ground move in a weird way when the camera moves.
//But this does:
return step(compare-SHADOW_BIAS, texture(shadowMap, coords.xy).r);
//With this code the shadows are at the correct place.
//===========================================================================HERE==========================================================================HERE=====================
}
//To create a smooth darkness falloff at the edge of the shadow map
float calcShadowMapVisibilityFalloff(in vec2 coords, in float falloffStart, in float gradient) {
float distFromTexCenter = length(coords * vec2(2.0) - vec2(1.0));
float falloff = (clamp(pow(distFromTexCenter, gradient), falloffStart, 1.0) - falloffStart) * (1/(1-falloffStart));
if(falloff > 1.0 || falloff < 0.0) {
falloff = 0;
}
return 1-falloff;
}
void main(void){
float shadowInvertedBrightness = 1.0;
for(int i = 0; i < shadowMaps.length(); i++)
{
float visibility = 1 - sampleVarianceShadowMap(shadowMaps[i], shadowCoords[i].xy, shadowCoords[i].z);
shadowInvertedBrightness -= (visibility/shadowMaps.length()) * calcShadowMapVisibilityFalloff(shadowCoords[i].xy, 0.85, 2.0);
}
shadowInvertedBrightness = clamp(shadowInvertedBrightness, 0.2, 1.0);
//.bgra because I save textures with the BGRA format (I've read its faster)
out_Color = texture(modelTexture, passTexCoords).bgra * vec4(shadowInvertedBrightness,shadowInvertedBrightness,shadowInvertedBrightness,1);
}
頂點着色器:
#version 330 core
//Vertex coords
in vec3 position;
//Texture coords
in vec2 texCoords;
//The MVP matrix of the entity
uniform mat4 MVPMat;
//The "To Shadow Map Space" matrix
uniform mat4[4] shadowMVPBiasMats;
//The Transformation matrix of the entity
uniform mat4 transformMat;
out vec2 passTexCoords;
//Shadow map sample coords
out vec4[4] shadowCoords;
void main(void) {
gl_Position = MVPMat * vec4(position, 1.0);
vec4 worldPos = transformMat * vec4(position, 1.0);
for(int i = 0; i < shadowMVPBiasMats.length(); i++) {
shadowCoords[i] = shadowMVPBiasMats[i] * worldPos;
}
passTexCoords = texCoords;
}
完整的代碼(示例項目,你可以在Eclipse中導入)和截圖:
- Screenshots and source code(着色器文件在src/ShadowTest/rendering /,屏幕截圖/)
系統信息:
- 操作系統:Windows主頁,版本:10.0.15063
- GPU:英特爾高清顯卡520
- GPU驅動程序版本:20.19.15.4642(通過Medion公司)
請提供更多信息。一些截圖等。你看到人們低估了你。這是因爲沒有辦法幫助你提供的數據。而且,GLSL是不夠的。你的問題可以在客戶端使用着色器輸入。 –
我會建議一個一個地測試你的shadowMap,首先刪除你的main,然後加上float visibility = 1;如果(shadowCoord [i] .z-SHADOW_BIAS> texture(shadowMap [i],shadowCoord [i] .xy).r){visibility = 0; } out_Color = texture(modelTexture,passTexCoords).bgra * vec4(visibility,visibility,visibility,1);並告訴我們你看到的一個。您也可以嘗試將影子地圖保存在磁盤上並在查看器中顯示它們 –
如果您需要更多代碼或屏幕截圖,請查看Google Drive鏈接。我也會嘗試Draykoon D說的。 – Wendelin