// Instanced quad shader

#type vertex
#version 450 core

layout(location = 0) in mat4 a_Transform;
layout(location = 4) in vec4 a_Color;
layout(location = 5) in float a_TexIndex;
layout(location = 6) in float a_TilingFactor;
layout(location = 7) in int a_ObjectID;

// Camera uniform buffer (binding = 0)
layout(std140, binding = 0) uniform CameraData
{
	mat4 u_ViewProjection;
	mat4 u_View;
	mat4 u_Projection;
	vec3 u_CameraPosition;
};

out vec4 v_Color;
out vec2 v_TexCoord;
out float v_TilingFactor;
flat out float v_TexIndex;
flat out int v_ObjectID;

const vec3 s_Positions[4] = vec3[](
    vec3(-0.5, -0.5, 0.0),
    vec3(0.5, -0.5, 0.0),
    vec3(0.5, 0.5, 0.0),
    vec3(-0.5, 0.5, 0.0));

const vec2 s_TexCoords[4] = vec2[](
    vec2(0.0, 0.0),
    vec2(1.0, 0.0),
    vec2(1.0, 1.0),
    vec2(0.0, 1.0));

void main()
{
    int vertexIndex = gl_VertexID % 4;
    vec4 worldPosition = a_Transform * vec4(s_Positions[vertexIndex], 1.0);

    v_Color = a_Color;
    v_TexCoord = s_TexCoords[vertexIndex];
    v_TilingFactor = a_TilingFactor;
    v_TexIndex = a_TexIndex;
    v_ObjectID = a_ObjectID;

    gl_Position = u_ViewProjection * worldPosition;
}

#type fragment
#version 450 core

layout(location = 0) out vec4 o_Color;
layout(location = 1) out int o_ObjectID;

in vec4 v_Color;
in vec2 v_TexCoord;
in float v_TilingFactor;
flat in float v_TexIndex;
flat in int v_ObjectID;

uniform sampler2D u_Textures[32];

void main()
{
    vec4 texColor = v_Color;

    switch (int(v_TexIndex))
    {
    case 0:
        texColor *= texture(u_Textures[0], v_TexCoord * v_TilingFactor);
        break;
    case 1:
        texColor *= texture(u_Textures[1], v_TexCoord * v_TilingFactor);
        break;
    case 2:
        texColor *= texture(u_Textures[2], v_TexCoord * v_TilingFactor);
        break;
    case 3:
        texColor *= texture(u_Textures[3], v_TexCoord * v_TilingFactor);
        break;
    case 4:
        texColor *= texture(u_Textures[4], v_TexCoord * v_TilingFactor);
        break;
    case 5:
        texColor *= texture(u_Textures[5], v_TexCoord * v_TilingFactor);
        break;
    case 6:
        texColor *= texture(u_Textures[6], v_TexCoord * v_TilingFactor);
        break;
    case 7:
        texColor *= texture(u_Textures[7], v_TexCoord * v_TilingFactor);
        break;
    case 8:
        texColor *= texture(u_Textures[8], v_TexCoord * v_TilingFactor);
        break;
    case 9:
        texColor *= texture(u_Textures[9], v_TexCoord * v_TilingFactor);
        break;
    case 10:
        texColor *= texture(u_Textures[10], v_TexCoord * v_TilingFactor);
        break;
    case 11:
        texColor *= texture(u_Textures[11], v_TexCoord * v_TilingFactor);
        break;
    case 12:
        texColor *= texture(u_Textures[12], v_TexCoord * v_TilingFactor);
        break;
    case 13:
        texColor *= texture(u_Textures[13], v_TexCoord * v_TilingFactor);
        break;
    case 14:
        texColor *= texture(u_Textures[14], v_TexCoord * v_TilingFactor);
        break;
    case 15:
        texColor *= texture(u_Textures[15], v_TexCoord * v_TilingFactor);
        break;
    case 16:
        texColor *= texture(u_Textures[16], v_TexCoord * v_TilingFactor);
        break;
    case 17:
        texColor *= texture(u_Textures[17], v_TexCoord * v_TilingFactor);
        break;
    case 18:
        texColor *= texture(u_Textures[18], v_TexCoord * v_TilingFactor);
        break;
    case 19:
        texColor *= texture(u_Textures[19], v_TexCoord * v_TilingFactor);
        break;
    case 20:
        texColor *= texture(u_Textures[20], v_TexCoord * v_TilingFactor);
        break;
    case 21:
        texColor *= texture(u_Textures[21], v_TexCoord * v_TilingFactor);
        break;
    case 22:
        texColor *= texture(u_Textures[22], v_TexCoord * v_TilingFactor);
        break;
    case 23:
        texColor *= texture(u_Textures[23], v_TexCoord * v_TilingFactor);
        break;
    case 24:
        texColor *= texture(u_Textures[24], v_TexCoord * v_TilingFactor);
        break;
    case 25:
        texColor *= texture(u_Textures[25], v_TexCoord * v_TilingFactor);
        break;
    case 26:
        texColor *= texture(u_Textures[26], v_TexCoord * v_TilingFactor);
        break;
    case 27:
        texColor *= texture(u_Textures[27], v_TexCoord * v_TilingFactor);
        break;
    case 28:
        texColor *= texture(u_Textures[28], v_TexCoord * v_TilingFactor);
        break;
    case 29:
        texColor *= texture(u_Textures[29], v_TexCoord * v_TilingFactor);
        break;
    case 30:
        texColor *= texture(u_Textures[30], v_TexCoord * v_TilingFactor);
        break;
    case 31:
        texColor *= texture(u_Textures[31], v_TexCoord * v_TilingFactor);
        break;
    default:
        break;
    }

    if (texColor.a == 0.0)
        discard;

    o_Color = texColor;
    o_ObjectID = v_ObjectID;
}