#version 140

#define DB_GRADIENT_MAX 16
#define DB_COMMAND_MAX  64

#define CMD_POINT 1
#define CMD_LINE  2
#define CMD_RECT  3
#define CMD_TEXT  4

#define STRIKE_INSET  -1
#define STRIKE_CENTER 0
#define STRIKE_OUTSET 1

in vec3 v_v3Position;
in vec2 v_v2TexCoords;
in int  v_iCmdIndex;

out vec4 f_Color;

uniform sampler2D      txForeground;
uniform sampler2D      txBackground;
uniform sampler2DArray txCharacters;

struct Gradient_t {
    float fPosition;
    float pad0;
    float pad1;
    float pad2;
    vec4  v4Color;
};

uniform GradientBlock
{
    Gradient_t vstGradientStops[DB_GRADIENT_MAX];
};

vec4 getGradientColor(float position, int index, int count)
{
    position = clamp(position, 0, 1);

    int i0 = 0;
    float p0 = vstGradientStops[index + i0].fPosition;

    int i1 = count - 1;
    float p1 = vstGradientStops[index + i1].fPosition;

    for (int i = 0; i < count; i++)
    {
        float px = vstGradientStops[index + i].fPosition;

        if (px > p0 && px <= position)
        {
            p0 = px;
            i0 = i;
        }

        if (px < p1 && px >= position)
        {
            p1 = px;
            i1 = i;
        }
    }

    vec4 c0 = vstGradientStops[index + i0].v4Color;
    vec4 c1 = vstGradientStops[index + i1].v4Color;

    float l = p1 - p0;
    float w = (l > 0) ? (position - p0) / (p1 - p0) : 0;

    return mix(c0, c1, w);
}

struct CommandCommon {
    int iCommand;
    int iStrikeKind;
    float fBorderRadius;
    int _padding;

    int iFgGradientIndex;
    int iFgGradientCount;
    int iBgGradientIndex;
    int iBgGradientCount;

    vec4 v4FillColor;
    vec4 v4BorderColor;
};

uniform CommandBlock
{
  CommandCommon vstCommands[DB_COMMAND_MAX];
};

void main(void)
{

}