105 lines
2.1 KiB
Go
105 lines
2.1 KiB
Go
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package render
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import (
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"fmt"
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"git.kirsle.net/apps/doodle/events"
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)
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// Engine is the interface for the rendering engine, keeping SDL-specific stuff
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// far away from the core of Doodle.
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type Engine interface {
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Setup() error
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// Poll for events like keypresses and mouse clicks.
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Poll() (*events.State, error)
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GetTicks() uint32
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// Draw presents the current state to the screen.
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Draw() error
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// Clear the full canvas and set this color.
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Clear(Color)
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DrawPoint(Color, Point)
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DrawLine(Color, Point, Point)
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DrawRect(Color, Rect)
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DrawText(Text, Rect) error
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// Delay for a moment using the render engine's delay method,
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// implemented by sdl.Delay(uint32)
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Delay(uint32)
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// Tasks that the Setup function should defer until tear-down.
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Teardown()
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Loop() error // maybe?
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}
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// Color holds an RGBA color value.
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type Color struct {
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Red uint8
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Green uint8
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Blue uint8
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Alpha uint8
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}
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func (c Color) String() string {
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return fmt.Sprintf(
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"Color<#%02x%02x%02x>",
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c.Red, c.Green, c.Blue,
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)
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}
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// Point holds an X,Y coordinate value.
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type Point struct {
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X int32
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Y int32
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}
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func (p Point) String() string {
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return fmt.Sprintf("Point<%d,%d>", p.X, p.Y)
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}
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// Rect has a coordinate and a width and height.
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type Rect struct {
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X int32
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Y int32
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W int32
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H int32
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}
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func (r Rect) String() string {
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return fmt.Sprintf("Rect<%d,%d,%d,%d>",
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r.X, r.Y, r.W, r.H,
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)
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}
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// Text holds information for drawing text.
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type Text struct {
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Text string
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Size int
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Color Color
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Stroke Color // Stroke color (if not zero)
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Shadow Color // Drop shadow color (if not zero)
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}
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func (t Text) String() string {
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return fmt.Sprintf("Text<%s>", t.Text)
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}
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// Common color names.
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var (
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Invisible = Color{}
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White = Color{255, 255, 255, 255}
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Grey = Color{153, 153, 153, 255}
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Black = Color{0, 0, 0, 255}
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SkyBlue = Color{0, 153, 255, 255}
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Blue = Color{0, 0, 255, 255}
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Red = Color{255, 0, 0, 255}
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Green = Color{0, 255, 0, 255}
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Cyan = Color{0, 255, 255, 255}
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Yellow = Color{255, 255, 0, 255}
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Magenta = Color{255, 0, 255, 255}
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Pink = Color{255, 153, 255, 255}
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)
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