[英]SSAO & Shadow mapping | Shadows do not work with the SSAO
我們引擎中的SSAO似乎正在運行,但是我無法讓SSAO與陰影貼圖一起使用。 這是當應用陰影時我當前遇到的錯誤的屏幕截圖。
而且,根據攝像機視圖和攝像機位置,有時會出現隨機陰影...
這是gbuffer頂點着色器。
#version 330 core
layout (location = 0) in vec3 positions;
layout (location = 1) in vec2 texCoords;
layout (location = 2) in vec3 normals;
out vec3 FragPos;
out vec3 ShadowFragPos;
out vec2 TexCoords;
out vec3 Normal;
uniform mat4 model;
uniform mat4 view;
uniform mat4 proj;
void main()
{
vec4 viewPos = view * model * vec4(positions, 1.0);
FragPos = viewPos.xyz;
TexCoords = texCoords;
mat3 normalMatrix = transpose(inverse(mat3(view * model)));
Normal = normalMatrix * normals;
gl_Position = proj * viewPos;
}
這是照明着色器。
#version 330 core
out vec4 FragColor;
in vec2 TexCoords;
uniform sampler2D gPosition;
uniform sampler2D gNormal;
uniform sampler2D gAlbedoSpec;
uniform sampler2D gShadowmap;
uniform sampler2D gSsao;
uniform vec3 cameraPos;
uniform mat4 lightSpaceMatrix;
vec3 Normal;
vec3 FragPos;
uniform vec3 lightPos;
float calculate_shadows(vec4 light_space_pos)
{
// perform perspective divide
vec3 projCoords = light_space_pos.xyz / light_space_pos.w;
// transform to [0,1] range
projCoords = projCoords * 0.5 + 0.5;
// get closest depth value from light's perspective (using [0,1] range fragPosLight as coords)
float closestDepth = texture(gShadowmap, projCoords.xy).r;
// get depth of current fragment from light's perspective
float currentDepth = projCoords.z;
// check whether current frag pos is in shadow
vec3 lightDir = normalize(vec3(2.0f, 4.0f, 1.0f) - FragPos);
float bias = max(0.05 * (1.0 - dot(Normal, lightDir)), 0.005);
float shadow = 0.0;
vec2 texelSize = 1.0 / textureSize(gShadowmap, 0);
// 8x8 kernel PCF
float x;
float y;
for (y = -3.5; y <= 3.5 ; y += 1.0)
{
for (x = -3.5; x <= 3.5 ; x += 1.0)
{
float pcfDepth = texture(gShadowmap, projCoords.xy + vec2(x, y) * texelSize).r;
shadow += currentDepth - bias > pcfDepth ? 1.0 : 0.0;
}
}
shadow /= 64.0;
return shadow;
}
void main(void)
{
FragPos = texture(gPosition, TexCoords).rgb;
Normal = texture(gNormal, TexCoords).rgb;
vec3 Diffuse = texture(gAlbedoSpec, TexCoords).rgb;
float Specular = texture(gAlbedoSpec, TexCoords).a;
float AmbientOcclusion = texture(gSsao, TexCoords).r;
vec3 lighting = vec3(0.3 * Diffuse * AmbientOcclusion);
vec3 viewDir = normalize(-FragPos);
vec3 lightDir = normalize(lightPos - FragPos);
vec3 diffuse = max(dot(Normal, lightDir), 0.0) * Diffuse * vec3(1.0f, 0.5f, 0.3f);
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = pow(max(dot(Normal, halfwayDir), 0.0), 8.0);
vec3 specular = vec3(1.0f, 0.5f, 0.3f) * spec * Specular;
float shadow = calculate_shadows(lightSpaceMatrix * vec4(FragPos, 1.0));
lighting += ((1.0 - shadow) * (diffuse + specular));
FragColor = vec4(lighting, 1.0f);
}
如下將紋理綁定到光通道中。
// bind the positions texture and store in the first texture slot/unit
glActiveTexture(GL_TEXTURE0); // texture unit 0
glBindTexture(GL_TEXTURE_2D, gbuffer.gPositions); // geometry positions
// bind the normals texture and store in the second texture slot/unit
glActiveTexture(GL_TEXTURE1); // texture unit 1
glBindTexture(GL_TEXTURE_2D, gbuffer.gNormals); // geometry normals
// bind the albedo & specular texture and store in the third texture slot/unit
glActiveTexture(GL_TEXTURE2); // texture unit 2
glBindTexture(GL_TEXTURE_2D, gbuffer.gAlbedoSpec); // geometry albedospec
// bind the albedo & specular texture and store in the third texture slot/unit
glActiveTexture(GL_TEXTURE3); // texture unit 3
glBindTexture(GL_TEXTURE_2D, gbuffer.gShadowmap); // geometry albedospec
glActiveTexture(GL_TEXTURE4); // texture unit 2
glBindTexture(GL_TEXTURE_2D, gbuffer.ssaoColorBuffer); // geometry albedospec
最后,這是lightSpaceMatrix的計算。
light_projection = glm::ortho(-10.0f, 10.0f, -10.0f, 10.0f, 1.0f, 7.5f);
light_view = glm::lookAt(glm::vec3(0.0f, 4.0f, 5.0f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
light_space_matrix = light_projection * light_view;
任何想法為什么會發生這種情況? 如何獲得與SSAO合作的陰影?
任何幫助深表感謝。
FragPos
是攝像機視圖空間的位置。
light_space_pos
,輸入參數到calculate_shadows
必須是一個夾子空間坐標,作為從光源看過。
這意味着當你做
float shadow = calculate_shadows(lightSpaceMatrix * vec4(FragPos, 1.0));
lightSpaceMatrix
必須是從攝影機視圖空間到光源的剪輯空間的轉換。
為此,您必須進行3個轉換:
相機視圖空間到世界空間。 這可以通過逆view
矩陣完成。
世界空間到光空間,這是通過light_view
的轉換。
光源視圖空間到光源剪輯空間,是通過light_projection
的轉換。
所以light_space_matrix = light_projection * light_view;
的設置light_space_matrix = light_projection * light_view;
還不夠,必須
light_space_matrix = light_projection * light_view * glm::inverse(view);
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