Demo 1 of 13 in category Nopper
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# OpenGL 3.3 with GLEW - Example 02
#
# @author Norbert Nopper norbert@nopper.tv
# @version 1.0
#
# Homepage: https://github.com/McNopper/OpenGL
#
# Copyright Norbert Nopper
#
# Modified for Tcl3D by Paul Obermeier 2010/09/01
# See www.tcl3d.org for the Tcl3D extension.
package require Tk
package require tcl3d
# Font to be used in the Tk listbox.
set g_Demo(listFont) {-family {Courier} -size 10}
# Obtain the name of this script file.
set g_Demo(scriptDir) [file dirname [info script]]
# Window size.
set g_Demo(winWidth) 640
set g_Demo(winHeight) 480
# Show errors occuring in the Togl callbacks.
proc bgerror { msg } {
tk_messageBox -icon error -type ok -message "Error: $msg\n\n$::errorInfo"
ExitProg
}
# Print info message into widget a the bottom of the window.
proc PrintInfo { msg } {
if { [winfo exists .fr.info] } {
.fr.info configure -text $msg
}
}
# Function for initialization.
proc Init {} {
global g_Demo g_Program
# Points of a triangle.
set pointList [list \
0.0 0.0 0.0 1.0 \
0.5 0.0 0.0 1.0 \
0.0 0.5 0.0 1.0 \
]
set pointVec [tcl3dVectorFromList GLfloat $pointList]
set pointVecSize [expr [llength $pointList] * [$pointVec elemsize]]
# Load the source of the vertex shader.
set vertexSource [tcl3dOglReadShaderFile [file join $g_Demo(scriptDir) "Vertex.vs"]]
# Load the source of the fragment shader.
set fragmentSource [tcl3dOglReadShaderFile [file join $g_Demo(scriptDir) "Fragment.fs"]]
set g_Program [tcl3dOglBuildProgram $vertexSource "" "" "" $fragmentSource]
# The VAO for the vertices etc.
set g_Demo(vao) [tcl3dVector GLuint 1]
glGenVertexArrays 1 $g_Demo(vao)
glBindVertexArray [$g_Demo(vao) get 0]
# The location of the vertex in the shader program
set vertexLocation [glGetAttribLocation [dict get $g_Program program] "vertex"]
# The VBO for the vertices.
set g_Demo(vertices) [tcl3dVector GLuint 1]
glGenBuffers 1 $g_Demo(vertices)
glBindBuffer GL_ARRAY_BUFFER [$g_Demo(vertices) get 0]
glBufferData GL_ARRAY_BUFFER $pointVecSize $pointVec GL_STATIC_DRAW
glUseProgram [dict get $g_Program program]
glVertexAttribPointer $vertexLocation 4 GL_FLOAT GL_FALSE 0 "NULL"
glEnableVertexAttribArray $vertexLocation
}
proc CreateCallback { toglwin } {
glClearColor 0.0 0.0 0.0 0.0
glClearDepth 1.0
}
proc ReshapeCallback { toglwin { w -1 } { h -1 } } {
set w [$toglwin width]
set h [$toglwin height]
glViewport 0 0 $w $h
}
proc DisplayCallback { toglwin } {
global g_Demo
glClear [expr $::GL_COLOR_BUFFER_BIT | $::GL_DEPTH_BUFFER_BIT]
if { ! $g_Demo(haveNeededVersion) } {
$toglwin swapbuffer
return
}
glDrawArrays GL_TRIANGLES 0 3
$toglwin swapbuffer
}
proc Cleanup {} {
global g_Demo g_Program
if { [info exists g_Demo(vertices)] } {
glDeleteBuffers 1 [$g_Demo(vertices) get 0]
$g_Demo(vertices) delete
}
if { [info exists g_Demo(vao)] } {
glDeleteVertexArrays 1 [$g_Demo(vao) get 0]
$g_Demo(vao) delete
}
if { [info exists g_Program] } {
tcl3dOglDestroyProgram $g_Program
}
# Unset all global variables.
# Needed when running the demo in the Tcl3D presentation framework.
foreach var [info globals g_*] {
uplevel #0 unset $var
}
}
# Put all exit related code here.
proc ExitProg {} {
exit
}
# Create the OpenGL window and some Tk helper widgets.
proc CreateWindow {} {
global g_Demo
frame .fr
pack .fr -expand 1 -fill both
# Create a Togl window with an OpenGL core profile using version 3.3.
# Reshape and Display callbacks are configured later after knowing if
# the needed OpenGL profile version is available.
togl .fr.toglwin -width $g_Demo(winWidth) -height $g_Demo(winHeight) \
-double true -depth true \
-createcommand CreateCallback \
-coreprofile true -major 3 -minor 3
set g_Demo(haveNeededVersion) true
set numRows 1
set haveGL3 [tcl3dOglHaveVersion 3]
if { ! $haveGL3 } {
set msgStr [format \
"Demo needs core profile 3.3. Only have GL version %s" \
[tcl3dOglGetVersion]]
set g_Demo(haveNeededVersion) false
incr numRows
} else {
set profile [tcl3dOglGetProfile .fr.toglwin]
if { [dict get $profile "coreprofile"] != true } {
set msgStr [format \
"Demo needs core profile 3.3. Only have compatibility profile %d.%d" \
[dict get $profile "major"] \
[dict get $profile "minor"]]
incr numRows
}
}
if { $g_Demo(haveNeededVersion) } {
# If OpenGL 3.3 or higher is available, initialize the buffers.
Init
}
# Now attach the Reshape and Display callbacks to the Togl window.
.fr.toglwin configure \
-reshapecommand ReshapeCallback \
-displaycommand DisplayCallback
listbox .fr.usage -font $g_Demo(listFont) -height $numRows
label .fr.info
grid .fr.toglwin -row 0 -column 0 -sticky news
grid .fr.usage -row 1 -column 0 -sticky news
grid .fr.info -row 2 -column 0 -sticky news
grid rowconfigure .fr 0 -weight 1
grid columnconfigure .fr 0 -weight 1
wm title . "Tcl3D demo: Nopper's core profile tutorials (Example 02 - Rendering of a triangle)"
# Watch for Esc key and Quit messages
wm protocol . WM_DELETE_WINDOW "ExitProg"
bind . <Key-Escape> "ExitProg"
.fr.usage insert end "Key-Escape Exit"
if { [info exists msgStr] } {
.fr.usage insert end $msgStr
.fr.usage itemconfigure end -background red
} else {
.fr.usage configure -state disabled
}
}
CreateWindow
ReshapeCallback .fr.toglwin
PrintInfo [tcl3dOglGetInfoString]
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