mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-26 03:38:55 +01:00
115 lines
3.0 KiB
Go
115 lines
3.0 KiB
Go
/*
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Copyright 2014 Hajime Hoshi
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package ebiten
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import (
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"github.com/hajimehoshi/ebiten/internal/opengl"
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"github.com/hajimehoshi/ebiten/internal/opengl/internal/shader"
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)
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// A Rect represents a rectangle.
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type Rect struct {
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X int
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Y int
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Width int
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Height int
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}
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// A TexturePart represents a part of a texture.
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type TexturePart struct {
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LocationX int
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LocationY int
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Source Rect
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}
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// A Drawer is the interface that draws itself.
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type Drawer interface {
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Draw(parts []TexturePart, geo GeometryMatrix, color ColorMatrix) error
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}
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// DrawWhole draws the whole texture.
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func DrawWhole(drawer Drawer, width, height int, geo GeometryMatrix, color ColorMatrix) error {
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parts := []TexturePart{
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{0, 0, Rect{0, 0, width, height}},
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}
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return drawer.Draw(parts, geo, color)
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}
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// A GraphicsContext is the interface that means a context of rendering.
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type GraphicsContext interface {
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Clear() error
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Fill(r, g, b uint8) error
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Texture(id TextureID) Drawer
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RenderTarget(id RenderTargetID) Drawer
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// TODO: ScreenRenderTarget() Drawer
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PushRenderTarget(id RenderTargetID)
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PopRenderTarget()
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}
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// Filter represents the type of filter to be used when a texture or a render
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// target is maginified or minified.
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type Filter int
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// Filters
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const (
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FilterNearest Filter = iota
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FilterLinear
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)
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// TextureID represents an ID of a texture.
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type TextureID int
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// IsNil returns true if the texture is nil.
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func (i TextureID) IsNil() bool {
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return i == 0
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}
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// RenderTargetID represents an ID of a render target.
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// A render target is essentially same as a texture, but it is assumed that the
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// all alpha of a render target is maximum.
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type RenderTargetID int
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// IsNil returns true if the render target is nil.
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func (i RenderTargetID) IsNil() bool {
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return i == 0
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}
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func u(x int, width int) float32 {
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return float32(x) / float32(opengl.AdjustSizeForTexture(width))
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}
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func v(y int, height int) float32 {
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return float32(y) / float32(opengl.AdjustSizeForTexture(height))
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}
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func textureQuads(parts []TexturePart, width, height int) []shader.TextureQuad {
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quads := make([]shader.TextureQuad, 0, len(parts))
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for _, part := range parts {
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x1 := float32(part.LocationX)
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x2 := float32(part.LocationX + part.Source.Width)
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y1 := float32(part.LocationY)
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y2 := float32(part.LocationY + part.Source.Height)
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u1 := u(part.Source.X, width)
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u2 := u(part.Source.X+part.Source.Width, width)
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v1 := v(part.Source.Y, height)
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v2 := v(part.Source.Y+part.Source.Height, height)
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quad := shader.TextureQuad{x1, x2, y1, y2, u1, u2, v1, v2}
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quads = append(quads, quad)
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}
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return quads
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}
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