learnopengl tutorial fragment shader for 2 points light - c++

Question

I have been following www.learnopengl.com tutorial and tried to load models using the method described. It works until the very end where it asks you to load the nanosuit with 2 points lights. I have copied the exact code from the tutorial with: camera, mesh, model, and shader classes however the issue is with the fragment shader. If I try a simple one like:
#version 330 core
in vec2 TexCoords;
out vec4 color;
uniform sampler2D texture_diffuse1;
void main()
{
color = vec4(texture(texture_diffuse1, TexCoords));
}
, the model is loaded and the textures too. But if try the solution given for 2 points lighting the texture is black:
#version 330 core
struct Material {
sampler2D texture_diffuse1;
sampler2D texture_specular1;
float shininess;
};
/* Note: because we now use a material struct again you want to change your
mesh class to bind all the textures using material.texture_diffuseN instead of
texture_diffuseN. */
struct PointLight {
vec3 position;
float constant;
float linear;
float quadratic;
vec3 ambient;
vec3 diffuse;
vec3 specular;
};
#define NR_POINT_LIGHTS 2
in vec3 fragPosition;
in vec3 Normal;
in vec2 TexCoords;
out vec4 color;
uniform vec3 viewPos;
uniform PointLight pointLights[NR_POINT_LIGHTS];
uniform Material material;
// Function prototypes
vec3 CalcPointLight(PointLight light, Material mat, vec3 normal, vec3 fragPos, vec3 viewDir);
void main()
{
vec3 result;
vec3 viewDir = normalize(viewPos - fragPosition);
vec3 norm = normalize(Normal);
for(int i = 0; i < NR_POINT_LIGHTS; i++)
result += CalcPointLight(pointLights[i], material, norm, fragPosition, viewDir);
color = vec4(result, 1.0f);
}
// Calculates the color when using a point light.
vec3 CalcPointLight(PointLight light, Material mat, vec3 normal, vec3 fragPos, vec3 viewDir)
{
vec3 lightDir = normalize(light.position - fragPos);
// Diffuse shading
float diff = max(dot(normal, lightDir), 0.0);
// Specular shading
vec3 reflectDir = reflect(-lightDir, normal);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), mat.shininess);
// Attenuation
float distance = length(light.position - fragPos);
float attenuation = 1.0f / (light.constant + light.linear * distance + light.quadratic * (distance * distance));
// Combine results
vec3 ambient = light.ambient * vec3(texture(mat.texture_diffuse1, TexCoords));
vec3 diffuse = light.diffuse * diff * vec3(texture(mat.texture_diffuse1, TexCoords));
vec3 specular = light.specular * spec * vec3(texture(mat.texture_specular1, TexCoords));
ambient *= attenuation;
diffuse *= attenuation;
specular *= attenuation;
return (ambient + diffuse + specular);
}
I also modified the mesh class as described in the fragment shader from:
glUniform1i(glGetUniformLocation(shader.Program, (name + number).c_str()), i);
to:
glUniform1i(glGetUniformLocation(shader.Program, ("material." + name + number).c_str()), i);
Is anyone having the same issue?

Answer 1

It seems like GLSL does not like function. If I take CalcPointLight() code and place it in main(), it works!
#version 330 core
struct Material {
sampler2D texture_diffuse1;
sampler2D texture_specular1;
float shininess;
};
/* Note: because we now use a material struct again you want to change your
mesh class to bind all the textures using material.texture_diffuseN instead of
texture_diffuseN. */
struct PointLight {
vec3 position;
float constant;
float linear;
float quadratic;
vec3 ambient;
vec3 diffuse;
vec3 specular;
};
#define NR_POINT_LIGHTS 2
in vec3 fragPosition;
in vec3 Normal;
in vec2 TexCoords;
out vec4 color;
uniform vec3 viewPos;
uniform PointLight pointLights[NR_POINT_LIGHTS];
uniform Material material;
void main()
{
vec3 result;
vec3 viewDir = normalize(viewPos - fragPosition);
vec3 norm = normalize(Normal);
vec3 lightDir = normalize(pointLights[0].position - fragPosition);
// Diffuse shading
float diff = max(dot(norm, lightDir), 0.0);
// Specular shading
vec3 reflectDir = reflect(-lightDir, norm);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
// Attenuation
float distance = length(pointLights[0].position - fragPosition);
float attenuation = 1.0f / (pointLights[0].constant + pointLights[0].linear * distance + pointLights[0].quadratic * (distance * distance));
// Combine results
vec3 ambient = pointLights[0].ambient * vec3(texture(material.texture_diffuse1, TexCoords));
vec3 diffuse = pointLights[0].diffuse * diff * vec3(texture(material.texture_diffuse1, TexCoords));
vec3 specular = pointLights[0].specular * spec * vec3(texture(material.texture_specular1, TexCoords));
ambient *= attenuation;
diffuse *= attenuation;
specular *= attenuation;
result = ambient+diffuse+specular;
color = vec4(result, 1.0f);
}
Edit: Found the answer there: GLSL sampler2D in struct. You can't instanciate a struct that contains an opaque type such as sampler2D.
Edit1: You can actually use those variables into a function without passing them as arguments since they are defined globally:
#version 330 core
struct Material {
sampler2D texture_diffuse1;
sampler2D texture_specular1;
float shininess;
};
/* Note: because we now use a material struct again you want to change your
mesh class to bind all the textures using material.texture_diffuseN instead of
texture_diffuseN. */
struct PointLight {
vec3 position;
float constant;
float linear;
float quadratic;
vec3 ambient;
vec3 diffuse;
vec3 specular;
};
#define NR_POINT_LIGHTS 2
in vec3 fragPosition;
in vec3 Normal;
in vec2 TexCoords;
out vec4 color;
uniform vec3 viewPos;
uniform PointLight pointLights[NR_POINT_LIGHTS];
uniform Material material;
vec3 CalcLights(int i);
void main()
{
vec3 result;
for(int i=0; i<NR_POINT_LIGHTS; i++)
result += CalcLights(i);
color = vec4(result, 1.0f);
}
vec3 CalcLights(int i) //viewPos fragPosition pointLights[] Normal material TexCoords
{
vec3 viewDir = normalize(viewPos - fragPosition);
vec3 norm = normalize(Normal);
vec3 lightDir = normalize(pointLights[i].position - fragPosition);
// Diffuse shading
float diff = max(dot(norm, lightDir), 0.0);
// Specular shading
vec3 reflectDir = reflect(-lightDir, norm);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
// Attenuation
float distance = length(pointLights[i].position - fragPosition);
float attenuation = 1.0f / (pointLights[i].constant + pointLights[i].linear * distance + pointLights[i].quadratic * (distance * distance));
// Combine results
vec3 ambient = pointLights[0].ambient * vec3(texture(material.texture_diffuse1, TexCoords));
vec3 diffuse = pointLights[0].diffuse * diff * vec3(texture(material.texture_diffuse1, TexCoords));
vec3 specular = pointLights[0].specular * spec * vec3(texture(material.texture_specular1, TexCoords));
ambient *= attenuation;
diffuse *= attenuation;
specular *= attenuation;
return (ambient+diffuse+specular);
}