ModelPartMixin is braking sharders.

[FrederikHeinrich]

Bug Description

Sodium ModelPartMixin is braking the model rendering.

Reproduction Steps

assets\minecraft\shaders\core\rendertype_entity_translucent.vsh

#version 150

#moj_import <light.glsl>
#moj_import <fog.glsl>

in vec3 Position, Normal;
in vec4 Color;
in vec2 UV0;
in ivec2 UV1, UV2;

uniform sampler2D Sampler0, Sampler1, Sampler2;

uniform mat4 ModelViewMat, ProjMat;
uniform int FogShape;

uniform vec3 Light0_Direction, Light1_Direction;

out float vertexDistance;
out vec4 vertexColor, lightMapColor, overlayColor, normal;
out vec2 texCoord0, texCoord1;
out vec3 a, b;

vec3 getCubeSize(int cube) {
    switch(cube) {
        case 2: // Body
        case 3: // Jacket
            return vec3(8, 12, 4);
        case 4: // Arms
        case 5:
        case 6:
        case 7:
            return vec3(3, 12, 4);
        case 8: // Legs
        case 9:
        case 10:
        case 11:
            return vec3(4, 12, 4);

    }

    return vec3(8, 8, 8);
}

vec2 getBoxUV(int cube) {
    switch(cube) {
        case 0: // Head
            return vec2(0, 0);
        case 1: // Hat
            return vec2(32, 0);
        case 2: // Body
            return vec2(16, 16);
        case 3: // Jacket
            return vec2(16, 32);
        case 4: // Right arm
            return vec2(40, 16);
        case 5: // Right sleave
            return vec2(40, 32);
        case 6:
            return vec2(32, 48);
        case 7: // Left Sleeve
            return vec2(48, 48);
        case 8: // Right Leg
            return vec2(0, 16);
        case 9: // Right Pant
            return vec2(0, 32);
        case 10: // Left Leg
            return vec2(16, 48);
        case 11: // Left Pant
            return vec2(0, 48);

    }
    return vec2(0, 0);
}

vec2 getUVOffset(int corner, vec3 cubeSize) {
    vec2 offset, uv;
    switch(corner / 4) {
        case 1: // BOTTOM
            offset = vec2(cubeSize.z + cubeSize.x, 0);
            uv = vec2(cubeSize.x, cubeSize.z);
            break;
        case 4: // LEFT
            offset = vec2(cubeSize.z + cubeSize.x, cubeSize.z);
            uv = vec2(cubeSize.z, cubeSize.y);
            break;
        case 2: // RIGHT
            offset = vec2(0, cubeSize.z);
            uv = vec2(cubeSize.x, cubeSize.y);
            break;
        case 5: // BACK
            offset = vec2(2 * cubeSize.z + cubeSize.x, cubeSize.z);
            uv = vec2(cubeSize.z, cubeSize.y);
            break;
        case 0: // TOP
            offset = vec2(cubeSize.z, 0);
            uv = vec2(cubeSize.x, cubeSize.z);
            break;
        case 3: // FRONT
			offset = vec2(cubeSize.z, cubeSize.z);
            uv = vec2(cubeSize.x, cubeSize.y);
            break;
    }

    switch(corner % 4) {
        case 0:
            offset += vec2(uv.x, 0);
            break;
        case 2:
            offset += vec2(0, uv.y);
            break;
        case 3:
            offset += vec2(uv.x, uv.y);
            break;
    }

    return offset;
}

void main() {
    gl_Position = ProjMat * ModelViewMat * vec4(Position, 1.0);

    a = b = vec3(0);
    if(textureSize(Sampler0, 0) == vec2(64, 64) && UV0.y <= 0.25 && (gl_VertexID / 24 != 6 || UV0.x <= 0.5)) {
        switch(gl_VertexID % 4) {
            case 0: a = vec3(UV0, 1); break;
            case 2: b = vec3(UV0, 1); break;
        }
		// 1 3 5 9 11 13 15 17
        int cube = (gl_VertexID / 24) % 24;
        int corner = gl_VertexID % 24;
        vec3 cubeSize = getCubeSize(cube) / 64;
        vec2 boxUV = getBoxUV(cube) / 64;
        vec2 uvOffset = getUVOffset(corner, cubeSize);
        texCoord0 = boxUV + uvOffset;
    } else {
        texCoord0 = UV0;
    }

    // vertexDistance = fog_distance(ModelViewMat, IViewRotMat * Position, FogShape);
    vertexDistance = length((ModelViewMat * vec4(Position, 1.0)).xyz);
    vertexColor = minecraft_mix_light(Light0_Direction, Light1_Direction, Normal, Color);
    lightMapColor = texelFetch(Sampler2, UV2 / 16, 0);
    overlayColor = texelFetch(Sampler1, UV1, 0);
    texCoord1 = UV0;
    normal = ProjMat * ModelViewMat * vec4(Normal, 0.0);
}```

### Log File

none

### Crash Report

![javaw_BkE8mL25LU](https://github.com/CaffeineMC/sodium-fabric/assets/40861522/d1d5cd5d-5347-435e-88f9-768d5d014a77)

[Lolothepro]

Core-shaders are not supported

[douira]

Is this even core shader related? Sodium doesn't have an issue with core shaders on entities afaik

[FrederikHeinrich]

Is this even core shader related? Sodium doesn't care about core shaders on entities afaik

i disabled CaffeineMC/sodium-fabric/src/main/java/net/caffeinemc/mods/sodium/mixin/features/render/entity/ModelPartMixin.java and it works.
so yes Sodium is messing with the shader handling.

[douira]

This bug report is very confusing because there is no description of what the bug is. And you didn't attach a log file or a crash report, only a screenshot for which you didn't describe what the problem is.

[FrederikHeinrich]

This bug report is very confusing because there is no description of what the bug is. And you didn't attach a log file or a crash report, only a screenshot for which you didn't describe what the problem is.

the skin part selection is not working correctly.
No crash, No log cuz it is just a visual misbehavior.

[0-x-2-2]

What is it supposed to look like? you didn't show anything. Are you sure there isn't a bug in your shader? The first issue I can see is that it uses gl_VertexID with hardcoded constants which make massive assumptions.

[FrederikHeinrich]

how it look:

how it supposed to look:

[0-x-2-2]

are the arms in the wrong direction?

[0-x-2-2]

i suspect this is related to the gl_VertexID usage in the code

[FrederikHeinrich]

the head would be the first thing I would notice...
but yes, several parts are wrong. (without sodium it is correct)