I work on C++ project for Android with OpenGL ES3, so I try to implement the shadow map with directional light, I understand the theory well but I never get it successfully rendered.
first I create the framebuffer which contains the depth map:
glGenFramebuffers(1, &depthMapFBO);
glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
glGenTextures(1, &depthMap);
glBindTexture(GL_TEXTURE_2D, depthMap);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthMap, 0);
glDrawBuffers(1, GL_NONE);
glReadBuffer(GL_NONE);
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
then I create a shader program that compiles the depth shader which is the following:
#version 300 es
precision mediump float;
layout (location = 0) in vec3 position;
layout (location = 4) in ivec4 BoneIDs;
layout (location = 5) in vec4 Weights;
const int MAX_BONES = 100;
uniform mat4 lightSpaceMatrix;
uniform mat4 model;
uniform bool skinned;
uniform mat4 gBones[MAX_BONES];
void main(){
vec4 nPos;
if(skinned){
mat4 BoneTransform = gBones[BoneIDs[0]] * Weights[0];
BoneTransform += gBones[BoneIDs[1]] * Weights[1];
BoneTransform += gBones[BoneIDs[2]] * Weights[2];
BoneTransform += gBones[BoneIDs[3]] * Weights[3];
nPos=BoneTransform * vec4(position, 1.0);
}
else
nPos = vec4(position, 1.0);
vec4 p=model * nPos;
gl_Position = lightSpaceMatrix * p;
}
and draw the scene using this shader program with the light space matrix using the following:
glCullFace(GL_FRONT);
double delta = GetCurrentTime() - firstFrame;
glm::mat4 camInv = glm::inverse(camera->getViewMatrix());
glm::mat4 lightSpaceProjection = glm::ortho(-40.0f, 40.0f, -40.0f, 40.0f, -1.0f, 100.0f);
glm::mat4 lightSpaceView = glm::lookAt(sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));
lightSpaceMatrix = lightSpaceProjection * (lightSpaceView*camInv) ;
glViewport(0, 0, SHADOW_WIDTH, SHADOW_HEIGHT);
glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
glClear(GL_DEPTH_BUFFER_BIT);
directDepthShader.use();
glUniformMatrix4fv(glGetUniformLocation(directDepthShader.getProgramID(), "lightSpaceMatrix"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
for (mesh_it it = castShadowMeshes.begin(); it != castShadowMeshes.end(); it++) {
it->get()->renderDepth(directDepthShader, delta);
}
glCullFace(GL_BACK);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
finally I render the scene with the regular shader program and bind the depth map to the shadowMap uniform with the following code:
glViewport(0, 0, width, height);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
phongShader.use();
if (sun != nullptr)
if (sun->castShadow)
glUniformMatrix4fv(glGetUniformLocation(phongShader.getProgramID(), "lightSpaceMatrix"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
this->setLightsUniforms(phongShader);
this->setViewUniforms(phongShader);
for (mesh_it it = phongMeshes.begin(); it != phongMeshes.end(); it++) {
if (it->get()->hasNormalMap) {
glUniform1i(glGetUniformLocation(phongShader.getProgramID(), "has_normal_map"), 1);
if (directlights.size() > 0) {
for (dlight_it it = this->directlights.begin(); it != this->directlights.end(); ++it) {
GLuint directLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("directLightPos[" + ToString((*it)->index) + "]").c_str());
glUniform3f(directLightPosLoc, (*it)->direction.x, (*it)->direction.y, (*it)->direction.z);
}
}
if (pointlights.size() > 0) {
for (plight_it it = this->pointlights.begin(); it != this->pointlights.end(); ++it) {
GLuint pointLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("pointLightPos[" + ToString((*it)->index) + "]").c_str());
glUniform3f(pointLightPosLoc, (*it)->position.x, (*it)->position.y, (*it)->position.z);
}
}
if (spotlights.size() > 0) {
for (slight_it it = this->spotlights.begin(); it != this->spotlights.end(); ++it) {
GLuint spotLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("spotLightPos[" + ToString((*it)->index) + "]").c_str());
glUniform3f(spotLightPosLoc, (*it)->position.x, (*it)->position.y, (*it)->position.z);
}
}
}
double first = GetCurrentTime() - firstFrame;
it->get()->textures = 0;
if (sun != nullptr)
if (sun->castShadow) {
glUniform1i(glGetUniformLocation(phongShader.getProgramID(), "shadowMap"), it->get()->textures);
glActiveTexture(GL_TEXTURE0 + it->get()->textures);
glBindTexture(GL_TEXTURE_2D, depthMap);
it->get()->textures++;
}
it->get()->Render(phongShader, first, deltaTime);
glBindTexture(GL_TEXTURE_2D, 0);
}
finally the shader vertex and fragment are the following:
Vertex:
#version 300 es
precision mediump float;
#define NR_DIRECT_LIGHTS 0
#define NR_POINT_LIGHTS 0
#define NR_SPOT_LIGHTS 0
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texCoord;
layout (location = 3) in vec3 tangent;
layout (location = 4) in ivec4 BoneIDs;
layout (location = 5) in vec4 Weights;
const int MAX_BONES = 100;
out vec2 TexCoords;
out vec3 Normal;
out vec3 tDirectLightPos[NR_DIRECT_LIGHTS];
out vec3 tPointLightPos[NR_POINT_LIGHTS];
out vec3 tSpotLightPos[NR_SPOT_LIGHTS];
out vec3 tViewPos;
out vec3 tFragPos;
out vec4 FragPosLightSpace;
// conditions //
uniform bool has_normal_map;
uniform bool skinned;
//
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
uniform vec3 viewPos;
uniform mat4 lightSpaceMatrix;
uniform mat4 gBones[MAX_BONES];
uniform vec3 directLightPos[NR_DIRECT_LIGHTS];
uniform vec3 pointLightPos[NR_POINT_LIGHTS];
uniform vec3 spotLightPos[NR_SPOT_LIGHTS];
void main(){
TexCoords = texCoord;
vec4 nPos;
vec3 N=transpose(inverse(mat3(model))) * normal;
if(skinned){
mat4 BoneTransform = gBones[BoneIDs[0]] * Weights[0];
BoneTransform += gBones[BoneIDs[1]] * Weights[1];
BoneTransform += gBones[BoneIDs[2]] * Weights[2];
BoneTransform += gBones[BoneIDs[3]] * Weights[3];
nPos=BoneTransform * vec4(position, 1.0);
Normal=(BoneTransform*vec4(N,0.0)).xyz;
}
else{
nPos = vec4(position, 1.0);
Normal=N;
}
gl_Position = projection*view * model * nPos;
vec3 FragPos = vec3(model * nPos);
if(has_normal_map){
mat3 normalMatrix = transpose(inverse(mat3(model)));
vec3 T = normalize(normalMatrix * tangent);
vec3 N = normalize(N);
T = normalize(T - dot(T, N) * N);
vec3 B = cross(N,T);
if (dot(cross(N, T), B) < 0.0)
T = T * -1.0;
mat3 TBN = transpose(mat3(T, B, N));
tViewPos=TBN*viewPos;
tFragPos=TBN*FragPos;
for(int i = 0; i < NR_DIRECT_LIGHTS-2; i++)
tDirectLightPos[i]=TBN*directLightPos[i];
for(int i = 0; i < NR_POINT_LIGHTS-2; i++)
tPointLightPos[i]=TBN*pointLightPos[i];
for(int i = 0; i < NR_SPOT_LIGHTS-2; i++)
tSpotLightPos[i]=TBN*spotLightPos[i];
}
else{
tViewPos=viewPos;
tFragPos=FragPos;
}
FragPosLightSpace = lightSpaceMatrix * vec4(FragPos,1.0);
}
Fragment:
#version 300 es
precision mediump float;
#define NR_DIRECT_LIGHTS 0
#define NR_POINT_LIGHTS 0
#define NR_SPOT_LIGHTS 0
out vec4 glFragColor;
vec2 poissonDisk[4] = vec2[](
vec2( -0.94201624, -0.39906216 ),
vec2( 0.94558609, -0.76890725 ),
vec2( -0.094184101, -0.92938870 ),
vec2( 0.34495938, 0.29387760 )
);
struct SpotLight{
vec3 position;
vec3 direction;
vec3 color;
float constant;
float linear;
float quadratic;
float cutoff;
float outerCutOff;
float intensity;
int castShadow;
};
struct PointLight{
vec3 position;
vec3 color;
float constant;
float linear;
float quadratic;
float intensity;
};
struct DirectLight {
vec3 direction;
vec3 color;
float intensity;
int castShadow;
};
in vec2 TexCoords;
in vec3 Normal;
in vec4 FragPosLightSpace;
in vec3 tDirectLightPos[NR_DIRECT_LIGHTS];
in vec3 tPointLightPos[NR_POINT_LIGHTS];
in vec3 tSpotLightPos[NR_SPOT_LIGHTS];
in vec3 tViewPos;
in vec3 tFragPos;
uniform bool Has_normal_map;
uniform sampler2D mat_diffuse;
uniform sampler2D mat_specular;
uniform sampler2D mat_normal;
uniform sampler2D shadowMap;
uniform vec3 matDiffuse;
uniform vec3 matSpecular;
uniform float shininess;
uniform float far_plane;
uniform DirectLight directLights[NR_DIRECT_LIGHTS];
uniform PointLight pointLights[NR_POINT_LIGHTS];
uniform SpotLight spotLights[NR_SPOT_LIGHTS];
vec3 calcDirectLight(DirectLight,vec3,vec3,vec3,vec3);
vec3 calcPointLight(PointLight,vec3,vec3,vec3,vec3);
vec3 calcSpotLight(SpotLight,vec3,vec3,vec3,vec3);
float directShadowCalculation();
void main(){
vec3 normal;
if(Has_normal_map){
normal=texture(mat_normal, TexCoords).rgb;
normal = normalize(normal * 2.0 - 1.0); // this normal is in tangent space
}
else
normal=normalize(Normal);
vec3 diffColor= matDiffuse+vec3(texture(mat_diffuse, TexCoords));
vec3 specColor= matSpecular+vec3(texture(mat_specular,TexCoords));
vec3 result;
result=vec3(0.0);
for(int i = 0; i < NR_DIRECT_LIGHTS-2; i++)
result += calcDirectLight(directLights[i],normal,tDirectLightPos[i],diffColor,specColor);
for(int i = 0; i < NR_POINT_LIGHTS-2; i++)
result += calcPointLight(pointLights[i],normal,tPointLightPos[i],vec3(0.0,0.2,0.4),specColor);
for(int i = 0; i < NR_SPOT_LIGHTS-2; i++)
result += calcSpotLight(spotLights[i],normal,tSpotLightPos[i],diffColor,specColor);
vec4 color =vec4(result,1.0);
float gamma = 2.2;
color.rgb = pow(color.rgb, vec3(1.0/gamma));
vec4 ambient=vec4(0.2,0.2,0.2,1.0)*vec4(diffColor,1.0);
glFragColor=ambient+color;
}
vec3 calcDirectLight(DirectLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
vec3 lightDir ;
if(Has_normal_map)
lightDir= normalize(tLightPos);
else
lightDir = normalize(light.direction);
float diff = max(dot(lightDir,norm), 0.0);
vec3 diffuse = light.color * diff *diffColor;
vec3 viewDir = normalize(tViewPos- tFragPos);
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = pow(max(dot(norm, halfwayDir), 0.0), 32.0);
vec3 specular = shininess* spec *specColor* light.color;
vec3 result;
if(light.castShadow==1){
float shadow = directShadowCalculation();
result =light.intensity* ( shadow* (diffuse + specular));
}
else
result =light.intensity* (diffuse + specular);
return result;
}
vec3 calcPointLight(PointLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
vec3 lightDir ;
if(Has_normal_map)
lightDir= normalize(tLightPos-tFragPos);
else
lightDir = normalize(light.position - tFragPos);
float diff = max(dot(lightDir,norm), 0.0);
vec3 diffuse = light.color * diff * diffColor;
vec3 viewDir = normalize(tViewPos- tFragPos);
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = pow(max(dot(norm, halfwayDir), 0.0), 16.0);
vec3 specular =shininess* specColor * spec * light.color;
vec3 result;
float distance = length(light.position - tFragPos);
float attenuation = 1.0f / (light.constant + light.linear * distance +light.quadratic * (distance * distance));
diffuse *= attenuation;
specular *= attenuation;
result=light.intensity*(diffuse+specular);
return result;
}
vec3 calcSpotLight(SpotLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
vec3 lightDir ;
if(Has_normal_map)
lightDir= normalize(tLightPos-tFragPos);
else
lightDir = normalize(light.position - tFragPos);
float diff = max(dot(lightDir,norm), 0.0);
vec3 diffuse = light.color * diff * diffColor;
vec3 viewDir = normalize(tViewPos- tFragPos);
float spec =0.0;
vec3 halfwayDir = normalize(lightDir + viewDir);
spec = pow(max(dot(norm, halfwayDir), 0.0), 16.0);
vec3 specular = shininess* light.color * spec * specColor;
// Spotlight (soft edges)
float theta = dot(lightDir, normalize(-light.direction));
float epsilon = (light.cutoff - light.outerCutOff);
float intensity = clamp((theta - light.outerCutOff) / epsilon, 0.0, 1.0);
diffuse *= intensity;
specular *= intensity;
// Attenuation
float distance = length(light.position - tFragPos);
float attenuation = 1.0f / (light.constant + light.linear * distance + light.quadratic * (distance * distance));
diffuse *= attenuation;
specular *= attenuation;
vec3 result = intensity*(diffuse+specular);
return result;
}
float directShadowCalculation(){
vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
projCoords = projCoords * 0.5 + 0.5;
float shadow = 1.0;
for (int i=0;i<4;i++){
if ( texture( shadowMap, -projCoords.xy + poissonDisk[i]/700.0 ).z < -projCoords.z ){
shadow-=0.2;
}
}
if(projCoords.z > 1.0)
shadow = 0.0;
return shadow;
}
sorry for all that code but I don't know where is the problem, it takes a week searching and debugging with no progress.
Edit
1- the light position vector is (-3.5f, 8.0f, 1.0f)
2- I changed the directShadowCalculation() to:
float directShadowCalculation(){
vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
projCoords = projCoords * 0.5 + 0.5;
float shadow = 1.0;
for (int i=0;i<4;i++){
if ( texture( shadowMap, projCoords.xy + poissonDisk[i]/700.0 ).z < projCoords.z ){
shadow-=0.2;
}
}
if(projCoords.z > 1.0)
shadow = 0.0;
return shadow;
}
this is the result
If you have to convert view space coordinates to the local space of the light source, then the
lightSpaceMatrixwould have to be setup as you do it:Because, you have to convert from view space to world space, by
camInv. Then you have to convert the world space coordinates, as seen from the light source (lightSpaceView). And finaly you have to project itlightSpaceProjection.But you convert directly from world coordinates to the local space of the light source, in the vertex shader:
Because of that you have to set up the
lightSpaceMatrixlike this:The projection matrix describes the mapping from 3D points of a scene, to 2D points of the viewport. It transforms from view (eye) space to the clip space, and the coordinates in the clip space are transformed to the normalized device coordinates (NDC) by dividing with the w component of the clip coordinates. The NDC are in range (-1,-1,-1) to (1,1,1). This is regardless of orthographic or perspective projection.
After dividing the projected fragment position (light space) by its w component, the
projCoordsare in the range from (-1, -1, -1) to (1, 1, 1).projCoords = projCoords * 0.5 + 0.5;transforms the XY coordinates to texture coordinates, and transforms the Z coordinate to a depth value in the range [0, 1].The inversions in the shadow test make no sense, since the content of the texture should be also a depth value in the range [0,1].
The shadow test should look somehow like this:
If
sun->directionis the direction up to the sun, thenlightSpaceViewhas to be set up like this:But, If
sun->directionis the direction in which the sun shines, thenlightSpaceViewhas to be set up like this:Since you use orthographic projection for the light and the origin of the light space matrix is near the origin of the worldspace, the near plane of the light projection should be far in the back of the light space. Otherwise the objects which are near to the the sun would be clipped, by the near plane of the light projection, when generating the light depth map.
Since the light calculations are done in view space, you have to convert the light positions from the world space to the view space:
See the WebGL example which demonstrates the algorithm:
See also