#include "config.h"

#include "gskgpulineargradientopprivate.h"

#include "gskgpuframeprivate.h"
#include "gskgpuprintprivate.h"
#include "gskrectprivate.h"

#include "gpu/shaders/gskgpulineargradientinstance.h"

#define VARIATION_SUPERSAMPLING (1 << 0)
#define VARIATION_REPEATING     (1 << 1)

typedef struct _GskGpuLinearGradientOp GskGpuLinearGradientOp;

struct _GskGpuLinearGradientOp
{
  GskGpuShaderOp op;
};

static void
gsk_gpu_linear_gradient_op_print_instance (GskGpuShaderOp *shader,
                                           gpointer        instance_,
                                           GString        *string)
{
  GskGpuLineargradientInstance *instance = (GskGpuLineargradientInstance *) instance_;

  if (shader->variation & VARIATION_REPEATING)
    gsk_gpu_print_string (string, "repeating");
  gsk_gpu_print_rect (string, instance->rect);
}

static const GskGpuShaderOpClass GSK_GPU_LINEAR_GRADIENT_OP_CLASS = {
  {
    GSK_GPU_OP_SIZE (GskGpuLinearGradientOp),
    GSK_GPU_STAGE_SHADER,
    gsk_gpu_shader_op_finish,
    gsk_gpu_shader_op_print,
#ifdef GDK_RENDERING_VULKAN
    gsk_gpu_shader_op_vk_command,
#endif
    gsk_gpu_shader_op_gl_command
  },
  "gskgpulineargradient",
  gsk_gpu_lineargradient_n_textures,
  sizeof (GskGpuLineargradientInstance),
#ifdef GDK_RENDERING_VULKAN
  &gsk_gpu_lineargradient_info,
#endif
  gsk_gpu_linear_gradient_op_print_instance,
  gsk_gpu_lineargradient_setup_attrib_locations,
  gsk_gpu_lineargradient_setup_vao
};

void
gsk_gpu_linear_gradient_op (GskGpuFrame            *frame,
                            GskGpuShaderClip        clip,
                            GskGpuColorStates       color_states,
                            gboolean                repeating,
                            const graphene_rect_t  *rect,
                            const graphene_point_t *start,
                            const graphene_point_t *end,
                            const graphene_point_t *offset,
                            const GskColorStop     *stops,
                            gsize                   n_stops)
{
  GskGpuLineargradientInstance *instance;
  GdkColorState *color_state = gsk_gpu_color_states_get_alt (color_states);

  g_assert (n_stops > 1);
  g_assert (n_stops <= 7);
  g_assert (gsk_gpu_color_states_is_alt_premultiplied (color_states));

  gsk_gpu_shader_op_alloc (frame,
                           &GSK_GPU_LINEAR_GRADIENT_OP_CLASS,
                           color_states,
                           (repeating ? VARIATION_REPEATING : 0) |
                           (gsk_gpu_frame_should_optimize (frame, GSK_GPU_OPTIMIZE_GRADIENTS) ? VARIATION_SUPERSAMPLING : 0),
                           clip,
                           NULL,
                           NULL,
                           &instance);

  gsk_gpu_rect_to_float (rect, offset, instance->rect);
  gsk_gpu_point_to_float (start, offset, instance->startend);
  gsk_gpu_point_to_float (end, offset, &instance->startend[2]);
  gdk_color_state_from_rgba (color_state, &stops[MIN (n_stops - 1, 6)].color, instance->color6);
  instance->offsets1[2] = stops[MIN (n_stops - 1, 6)].offset;
  gdk_color_state_from_rgba (color_state, &stops[MIN (n_stops - 1, 5)].color, instance->color5);
  instance->offsets1[1] = stops[MIN (n_stops - 1, 5)].offset;
  gdk_color_state_from_rgba (color_state, &stops[MIN (n_stops - 1, 4)].color, instance->color4);
  instance->offsets1[0] = stops[MIN (n_stops - 1, 4)].offset;
  gdk_color_state_from_rgba (color_state, &stops[MIN (n_stops - 1, 3)].color, instance->color3);
  instance->offsets0[3] = stops[MIN (n_stops - 1, 3)].offset;
  gdk_color_state_from_rgba (color_state, &stops[MIN (n_stops - 1, 2)].color, instance->color2);
  instance->offsets0[2] = stops[MIN (n_stops - 1, 2)].offset;
  gdk_color_state_from_rgba (color_state, &stops[1].color, instance->color1);
  instance->offsets0[1] = stops[1].offset;
  gdk_color_state_from_rgba (color_state, &stops[0].color, instance->color0);
  instance->offsets0[0] = stops[0].offset;
}