Shadows Are bright on OpenGL, fine in Vulkan

[martsbradley]

Hi Folks,

I am learning wpgu, the program is working and rendering on Linux with Vulkan and in the browser with opengl.

Hoping to get help to fix an issue with the shadows in the scene.

    let instance = wgpu::Instance::new(&wgpu::InstanceDescriptor {
        #[cfg(not(target_arch = "wasm32"))]
        backends: wgpu::Backends::PRIMARY,
        #[cfg(target_arch = "wasm32")]
        backends: wgpu::Backends::GL,
        ..Default::default()
    });

My issue is with shadows in the rendered scene. In the native Linux application the shadows cast are dark and that looks good to me, but in the browser the shadows cast are white/bright.

@vertex
fn vs_main(
    input: VertexInput,
) -> VertexOutput {
    var out: VertexOutput;
    out.tex_coords = input.tex_coords;
    out.clip_position = camera.view_proj * model_transform.model_transform *
                                    vec4<f32>(input.position, 1.0);
    
    let model = mat3x3<f32>(model_transform.model_transform[0].xyz,
                            model_transform.model_transform[1].xyz,
                            model_transform.model_transform[2].xyz);

    out.normal = model * input.normal;
    return out;
}

@fragment
fn fs_main(input: VertexOutput) -> @location(0) vec4<f32> {
    
    let lightDir = normalize(vec3(-0.5, 3.0, 1.0));
    let diffuse = max(dot(normalize(input.normal), lightDir), 0.0);
    let color = material.base_color * diffuse;

    let uv_coords = input.tex_coords;
    return textureSample(t_diffuse, s_diffuse, uv_coords) * color;
}

Things I have checked:

• Ensured that the textures are Rgba8UnormSrgb.
• Tested the shader with and without texture sampling, with and without color.
• Looked at settings around target_arch = "wasm32") but did not find reason for the light shadows.
• Tried Firefox and chrome, tho both are on Linux.

thanks
Martin

[martsbradley]

Hi Folks,

I got this issue resolved.

The shader code below working in the browser correctly.

I'll have to find out why.

@fragment
fn fs_main(input: VertexOutput) -> @location(0) vec4<f32> {

    let normal = normalize(input.normal);

    let lightDir = normalize(vec3(-0.5, 1.0, 1.0));

    let diffuse = max(dot(normal, lightDir), 0.1);

    let tex = textureSample(t_diffuse, s_diffuse, input.tex_coords);

    let lit = tex.rgb * material.base_color.rgb * diffuse;

    return vec4(lit, 1.0);
}

thanks,
Martin