OpenGL: Difference between revisions

Line 2,058:

=={{header|Phix}}==

Adapted from the included demo\Arwen32dibdemo\shadepol.exw, draws the same thing as the image at the top of this page, but (as per the talk page) does not use openGL, just windows api (BitBlt etc) and some low-level fully open source routines (all included). Note this is windows 32bit only, whereas the pGUI example below it runs on windows/linx, 32/64bit.

include demo\Arwen32dibdemo\a32dpoly.ew

a32Dib0 screen_dib = 0

integer dx = 0, dy = 0, dw = 0, dh = 0

constant win = create(Window, "Arwen32Dib bitmap shaded triangle demo", 0, 0, Default, Default, 480, 300, 0)

function winHandler(integer id, integer msg, atom wParam, object lParam)

sequence rect

if id or object(lParam) then end if -- suppress warnings

if msg=WM_PAINT then

if sequence(screen_dib) then

clearDib(screen_dib, {0, 0, 0})

drawShadedPolygonToDib(screen_dib, {{dx, dy}, {dx, dh-dy}, {dw-dx, dh-dy}}, {{255, 0, 0}, {0, 0, 255}, {0, 255, 0}})

drawDib(win, screen_dib, 0, 0, 0, 0, screen_dib[DibWidth]-1, screen_dib[DibHeight]-1)

end if

elsif msg=WM_SIZE then

rect = getClientRect(win)

dw = rect[3]

dh = rect[4]

dx = floor(dw/4)+1

dy = floor(dh/4)+1

if sequence(screen_dib) then killDib(screen_dib) end if

screen_dib = newDib(dw, dh)

elsif msg=WM_CHAR

and wParam=VK_ESCAPE then

closeWindow(win)

end if

return 0

end function

setHandler(win, routine_id("winHandler"))

WinMain(win, SW_NORMAL)

if sequence(screen_dib) then killDib(screen_dib) end if

And here is a proper openGL version, translated from Lua, and included in the distro as demo\pGUI\triangle.exw:

This can be run online [http://phix.x10.mx/p2js/OpenGL.htm here], also works on desktop/Phix.

You can find older windows 32bit only and OpenGL 1.0 verions [[OpenGL/Phix here]].

--

-- demo\rosetta\OpenGL.exw

-- =======================

--

with javascript_semantics

requires("1.0.1")

include pGUI.e

include opengl.e

Ihandln dlg

function resize_cb(Ihandle /*ih*/, integer width, integer height)

Ihandle canvas

glViewport(0, 0, width, height)

glMatrixMode(GL_PROJECTION)

glLoadIdentity()

glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0)

glMatrixMode(GL_MODELVIEW)

return IUP_DEFAULT

end function

~~function~~ ~~action~~~~(Ihandle~~ ~~/*ih*/)~~

constant fragment_shader = """

precision highp float;

varying vec4 v_color;

glClearColor(0.3,0.3,0.3,0.0)

void main(void) {

glClear(GL_COLOR_BUFFER_BIT+GL_DEPTH_BUFFER_BIT)

// "Varying" variables are implicitly interpolated across triangles.

gl_FragColor = v_color;

glShadeModel(GL_SMOOTH)

}""",

~~glLoadIdentity~~()

vertex_shader = """

attribute vec3 a_position;

glTranslate(-15.0, -15.0, 0.0)

attribute vec4 a_color;

varying vec4 v_color;

glBegin(GL_TRIANGLES)

void main(void) {

glColor(1.0, 0.0, 0.0)

gl_Position = vec4(a_position, 1.0);

glVertex(0.0, 0.0)

v_color = a_color;

glColor(0.0, 1.0, 0.0)

}"""

glVertex(30.0, 0.0)

glColor(0.0, 0.0, 1.0)

glVertex(0.0, 30.0)

glEnd()

glFlush()

function get_shader(string src, integer stype)

return IUP_DEFAULT

integer shader = glCreateShader(stype)

glShaderSource(shader, src)

glCompileShader(shader)

if not glGetShaderParameter(shader, GL_COMPILE_STATUS) then

crash(glGetShaderInfoLog(shader))

end if

return shader

end function

constant vertices = { -0.5, -0.5, 0, -- (bl)

Ihandln dialog

+0.5, -0.5, 0, -- (br)

Ihandle canvas

-0.5, +0.5, 0 }, -- (tl)

-- +0.5, +0.5, 0 }, -- (tr)

colours = { 1, 0, 0, 1, -- red (bl)

0, 1, 0, 1, -- green (br)

0, 0, 1, 1 } -- blue (tl)

~~function~~ ~~map_cb~~(~~Ihandle /*ih*/~~)

procedure set_shader()

IupGLMakeCurrent(canvas)

integer ~~{~~~~width, height}~~ = ~~IupGetIntInt~~(~~dialog, "RASTERSIZE"~~)

integer shaderProgram = glCreateProgram()

{} = ~~resize_cb~~(~~dialog~~, ~~width~~, ~~height~~)

glAttachShader(shaderProgram, get_shader(vertex_shader,GL_VERTEX_SHADER))

glAttachShader(shaderProgram, get_shader(fragment_shader,GL_FRAGMENT_SHADER))

return IUP_DEFAULT

~~end~~ ~~function~~

glLinkProgram(shaderProgram)

if not glGetProgramParameter(shaderProgram, GL_LINK_STATUS) then

crash(glGetProgramInfoLog(shaderProgram))

end if

glUseProgram(shaderProgram)

// Get the indexes to communicate vertex attributes to the program.

integer positionAttr = glGetAttribLocation(shaderProgram, "a_position"),

colorAttr = glGetAttribLocation(shaderProgram, "a_color")

IupOpen<span~~ style~~="color~~: ~~#0000FF;">()

// And specify that we will be actually delivering data to those attributes.

~~IupGLCanvasOpen~~()

glEnableVertexAttribArray(positionAttr)

glEnableVertexAttribArray(colorAttr)

// Store vertex positions and colors in array buffer objects.

canvas = IupGLCanvas(Icallback("action"), "RASTERSIZE=640x480")

~~<span~~ ~~style="color:~~ ~~#7060A8;">IupSetCallback<span~~ ~~style="color:~~ ~~#0000FF;">(<span~~ ~~style="color: #000000;">canvas~~, ~~"RESIZE_CB"~~, ~~Icallback~~(~~"resize_cb")~~)

integer positionBuffer = glCreateBuffer()

glBindBuffer(GL_ARRAY_BUFFER, positionBuffer)

{integer size, atom pData} = glFloat32Array(vertices)

glBufferData(GL_ARRAY_BUFFER, size, pData, GL_STATIC_DRAW)

glEnableVertexAttribArray(positionBuffer)

integer colorBuffer = glCreateBuffer()

glBindBuffer(GL_ARRAY_BUFFER, colorBuffer)

{size, pData} = glFloat32Array(colours)

glBufferData(GL_ARRAY_BUFFER, size, pData, GL_STATIC_DRAW)

glEnableVertexAttribArray(colorBuffer)

glEnable(GL_DEPTH_TEST)

// Specify the array data to render.

// 3 and 4 are the lengths of the vectors (3 for XYZ, 4 for RGBA).

glBindBuffer(GL_ARRAY_BUFFER, positionBuffer)

glVertexAttribPointer(positionAttr, 3, GL_FLOAT, false, 0, 0)

glEnableVertexAttribArray(positionAttr)

glBindBuffer(GL_ARRAY_BUFFER, colorBuffer)

glVertexAttribPointer(colorAttr, 4, GL_FLOAT, false, 0, 0)

glEnableVertexAttribArray(colorAttr)

end procedure

~~dialog~~ ~~= IupDialog(~~~~canvas,~~ ~~"MAP_CB"~~~~, Icallback~~~~<span~~ ~~style="color: #0000FF;">(~~"map_cb"), "TITLE=Triangle, SHRINK=YES")

bool drawn = false

~~IupShow~~(~~dialog~~)

function action(Ihandle /*ih*/)

if platform()!=JS then

if not drawn or platform()!=JS then

glClearColor(0.3, 0.3, 0.3, 1.0)

IupMainLoop()

~~dialog~~ = ~~IupDestroy~~(~~dialog~~)

integer {w,h} = IupGetIntInt(canvas,"DRAWSIZE")

~~IupClose~~()

glViewport(0, 0, w, h)

~~end~~ if

glClear(GL_COLOR_BUFFER_BIT || GL_DEPTH_BUFFER_BIT)

// Draw triangles using the specified arrays.

integer numVertices = length(vertices)/3 // 3 coordinates per vertex

glDrawArrays(GL_TRIANGLES, 0, numVertices)

// Check for errors.

while true do

integer e = glGetError()

if e=GL_NO_ERROR then exit end if

printf(1,"GL error %d\n", e)

end while

glFlush()

drawn = true

end if

return IUP_DEFAULT

end function

procedure main()

IupOpen()

canvas = IupGLCanvas(Icallback("action"), "RASTERSIZE=640x480")

dlg = IupDialog(canvas, "TITLE=OpenGLShader, SHRINK=YES")

IupMap(dlg)

set_shader()

IupShow(dlg)

if platform()!=JS then

IupMainLoop()

dlg = IupDestroy(dlg)

IupClose()

end if

end procedure

main()